Thứ Ba, 5 tháng 7, 2016

Anybody good at algebra? part 1


Boomstick777

Does anybody know how you would make 'k' the subject of the equation? See the pic attached. Any help would be appreciated..

http://i51.tinypic.com/2mnj3uf.jpg

The Howling Wolves

I know how but it would be better if you did your own homework.
Remember what you do to one side of the = sign you do to the other side.
hint....multiply both sides by k then divide each side by "a"
k=????????/

Copyright

k=sqr(b)/a

BugMeister

multiply both sides by root b then turn the whole thing upside down..

The Howling Wolves

Quote�� Quote: Originally Posted by Copyright View Post
k=sqr(b)/a

You get an "A" but go to the back of the room...Let boomstick figure it out!

Boomstick777

Quote�� Quote: Originally Posted by The Howling Wolves View Post
I know how but it would be better if you did your own homework.
Remember what you do to one side of the = sign you do to the other side.
hint....multiply both sides by k then divide each side by "a"
k=????????/
Thanks for your reply. k = b^2/a? I just don't get the method of this I need an example so can do the rest...

Does the sqr'b' stay the same even though it swapped sides? I thought it would become b^2?

sportscout

Does making k the subject of the equation mean the same as solving for k? Is this the new math?

The Howling Wolves

Find out what you each is asking for then do whatever it takes to get it alone on one side.
Then do the same to the other side..
In the first one you multiplied both sides by k
then divided by "a" to both sides to get k=b^2/a

Do that to the rest of them....

Boomstick777

Quote�� Quote: Originally Posted by The Howling Wolves View Post
Find out what you each is asking for then do whatever it takes to get it alone on one side.
Then do the same to the other side..
In the first one you multiplied both sides by k
then divided by "a" to both sides to get k=b^2/a

Do that to the rest of them....
Does the (Square root of b) stay as sqr(b) or change to b^2 (b,squared)? Im confused becasuce thought there would be more work to do, it looks like the 'k' has just been swapped out for the 'a'..

BugMeister

the answer to Q.a is the easiest, since it just involves shifting the three expressions around
Q.b is slightly more complex since it involves balancing the equation by doing some arithmetic

- remember that what you do to one side of the equation, you must also do to the other..
so - for example, taking 2 from the right side means that you also have to do the same to the left..

you are not being asked to simplify the equations - just to rearrange them..

SledgeDG

Howling Wolf is right...Basic rule with equations is whatever you do...always do it to both sides

@sportscout: apparently that's what they call it now. when I was at school, it was solve for k...For some reason "they" think they have to change terminology every decade (or so).

@Bugmeiser: Close.. but you might want to rethink that procedur
Edit, since you postet again: I refer to this
Quote:
multiply both sides by root b then turn the whole thing upside down
-DG

Boomstick777

Im still lost lol, if someone could break down the steps it would be awesome. Once I have the method figured out im sure these will seem easy, its all new to me I have no idea how to do a or b.. I know about balancing the sides, 'the basics' I don't understand how in question 'a' how the Square root of b stays as the square root of b if it changes sides etc..

BugMeister

Quote�� Quote: Originally Posted by SledgeDG View Post
Howling Wolf is right...Basic rule with equations is whatever you do...always do it to both sides

@sportscout: apparently that's what they call it now. when I was at school, it was solve for k...For some reason "they" think they have to change terminology every decade (or so).

@Bugmeiser: Close.. but you might want to rethink that procedur
Edit, since you postet again: I refer to this
Quote:
multiply both sides by root b then turn the whole thing upside down
-DG
I was standing on me head at the time..!!

SledgeDG

With an operation involving roots you always have 2 options:
Option 1 : solve the root (extremely unpracticable)
Option 2: use the whole thing as 1 expression (which means it doesn't change when its been "moved" to the other side
I hope that's a bit clearer

-DG

BugMeister

Quote�� Quote: Originally Posted by Boomstick777 View Post
Im still lost lol, if someone could break down the steps it would be awesome. Once I have the method figured out im sure these will seem easy, its all new to me I have no idea how to do a or b.. I know about balancing the sides, 'the basics' I don't understand how in question 'a' how the Square root of b stays as the square root of b if it changes sides etc..
think of root b as an expression..

- it's a bit like the Time = Distance/Speed formula..

all you're doing is moving the expressions around to suit their use:

Distance = Speed.Time
Speed = Distance/Time

The Howling Wolves

Quote�� Quote: Originally Posted by Boomstick777 View Post
Im still lost lol, if someone could break down the steps it would be awesome. Once I have the method figured out im sure these will seem easy, its all new to me I have no idea how to do a or b.. I know about balancing the sides, 'the basics' I don't understand how in question 'a' how the Square root of b stays as the square root of b if it changes sides etc..

We broke down the first one now you have to do the rest...
If I fish for you ............you won't learn how to fish ...you will starve!

Boomstick777

Ok I think I got question 'a' figured out..

a= Sqr(b)/k
becomes
a x k = Sqr(b) xk
a x k = Sqr(b)
a x k/a = Sqr(b)/a
so
k = Sqr(b)/a

Question 'b' is harder how do I just get the 'b' from the sqr(b)? Hmm

BugMeister

I'd just leave it as root b

The Howling Wolves

a-2= root of b over k
k(a-2) = root of b

SledgeDG

Remember: sqr(b)*sqr(b) = b

The Howling Wolves

Quote�� Quote: Originally Posted by SledgeDG View Post
Remember: sqr(b)*sqr(b) = b
Ya Sledge.....but wanted him to get that far and ask the ?

I am amazed that I can still recall this being I graduated from HS in 1962!
College in 71 with serving our country in between.

profdlp

Quote�� Quote: Originally Posted by Boomstick777 View Post
...Question 'b' is harder how do I just get the 'b' from the sqr(b)? Hmm
Picture it using actual numbers.

If you had sqr(9) on one side, what then?
Square both sides.
Your sqr(9) magically becomes just "9", because:

sqr(9) X sqr(9) = 9

Remember what BugMeister said:
Quote:
...what you do to one side of the equation, you must also do to the other...
Whatever is on the other side is also squared and becomes {itself} X {itself}


EDIT:
Quote�� Quote: Originally Posted by SledgeDG View Post
Remember: sqr(b)*sqr(b) = b
Clicked the wrong thing while replying and had to start over. It took you a lot less words to say what I was trying to tell him.

BugMeister

Umm..... I'm not a mathemetician, sorry :/

SledgeDG

- on reflection, neither am I

heh, heh..!!

profdlp

@THW:I didn't want to give him the result...rather have him recall basic rules. sorry if in doing so I spoiled your plan.
I'm actually enjoying this...haven't had the need to recall those calculations for pretty much an eternity now either

@Prof: my explanation is shorter... true but some ppl might understand better if they go the long way around

Perhaps I should register with Big Y (they run a homework helpline over here)

-DG

profdlp

Quote�� Quote: Originally Posted by BugMeister View Post
- on reflection, neither am I

heh, heh..!!
Very nice, lol. I could maybe do it, but I despise doing math. :/

madtownidiot

Quote�� Quote: Originally Posted by Benjamin Hall View Post
Umm..... I'm not a mathemetician, sorry :/
Math is just a set of rules. Play the game right and use the rules in their proper order and you'll win every time.

(Easier said than done, I know.)

It's no fun, but LOTS of practice is the best idea. You wouldn't shoot one free throw, sink it, then decide you had it down pat. But doing it over and over and over and...

Guest

Don't confuse me with your foreign language talk D=

Ehhhh

Guest

What? Don't they play basketball in Wisconsin?

Guest

No, what he's saying is in Wisconsin, people don't need to practice at anything. We always get it done right the first time.

arkhi

I miss math so much I feel like doing your homework LOL. Let me think about it. Hmmm..

EDIT: So I wanted to use MS Math so I can template equations so it's easier to understand and that solve it a bit, but that thing freaking did it for me. So here it is. I'm going to leave the last 2 steps out since I don't want to spoon feed. The last number is up to you okay?

Boomstick777

Is this the correct answer for question 'b'

b = k/a + 2

I used this method
a = sqr(b)/k + 2
a x
sqr(b) = sqr(b)/k + 2 xsqr(b)
a x b = k + 2
a x b/a = k/a +2


Answer - b = k/a +2

Kirsch

When did they add letters

Francis93

Nah. I suck at Algebra.

Dwarf

Let's go through this step by step.

a = sqr (b) / k + 2

sqr (b) / k = a - 2

sqr (b) = k (a -2)

sqr (b) = ka - 2k

b = (ka - 2k) x (ka - 2k)

b = k�a� - 4k�a + 4k� (answer)

Check using a = 6 and k = 3

b = (3� x 6�) - (4 x 3� x 6) + (4 x 3�)

b = 324 - 216 + 36

b = 144

Substituting b = 144 into the first equation, a = sqr (b) / k + 2, we get

a = (sqr (144) / 3) + 2

a = (12 / 3) + 2

a = 4 + 2

a = 6

So the answer is

b = k�a� - 4k�a + 4k�

Not bad, considering that it is about 30yrs since I did any Algebra. Hopefully, this should help you with the rest of the questions if you approach them in a similar way. Don't forget to do the checking, substituting actual numbers, as shown above. You will need to work out for yourself suitable numbers to use at this step.

Kirsch

Nice Job Dwarf!!

mickey megabyte

anybody good at washing up?

i've got a nice pile of dirty dishes growing in my kitchen..

Dwarf

Quote�� Quote: Originally Posted by Kirsch View Post
Nice Job Dwarf!!
Thanks.
Quote�� Quote: Originally Posted by mickey megabyte View Post
anybody good at washing up?

i've got a nice pile of dirty dishes growing in my kitchen..
I think I'll give that one a miss.

The Howling Wolves

Quote�� Quote: Originally Posted by Dwarf View Post
Let's go through this step by step.

a = sqr (b) / k + 2

sqr (b) / k = a - 2

sqr (b) = k (a -2)

sqr (b) = ka - 2k

b = (ka - 2k) x (ka - 2k)

b = k�a� - 4k�a + 4k� (answer)

Check using a = 6 and k = 3

b = (3� x 6�) - (4 x 3� x 6) + (4 x 3�)

b = 324 - 216 + 36

b = 144

Substituting b = 144 into the first equation, a = sqr (b) / k + 2, we get

a = (sqr (144) / 3) + 2

a = (12 / 3) + 2

a = 4 + 2

a = 6

So the answer is

b = k�a� - 4k�a + 4k�

Not bad, considering that it is about 30yrs since I did any Algebra. Hopefully, this should help you with the rest of the questions if you approach them in a similar way. Don't forget to do the checking, substituting actual numbers, as shown above. You will need to work out for yourself suitable numbers to use at this step.
Dwarf,
Nice job going step by step in solving his problem.
Could have done that early on in the post but thought it was important for the OP to practice and learn on his own. Isn't that the way we learned how to algebra?

Dwarf

I'm leaving the rest for him to work out on his own. Besides, the image isn't very clear with the other equations.

profdlp

Quote�� Quote: Originally Posted by The Howling Wolves View Post
...thought it was important for the OP to practice and learn on his own. Isn't that the way we learned how to algebra?
I paid some fat kid with glasses to take my tests for me.

Much easier.

(I made that up, Benjamin. Don't get any ideas.)

The Howling Wolves

Was looking for something else and ran across this little sign...may have to click on it!
Name:  math_sign.gif  Views: 23  Size:  19.8 KB

Enjoy your day...

Dwarf

Just noticed that I can reduce the final answer down a bit further. I'll leave him to work that out for himself.

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