Math Is Fun Forum

maths noob1

Guest

rearranging formulae

we have a test tomorow and dont have a clue how to do this. can someone show me as well as the steps if u have the time with the answer.
these are some questions we got during class(make x the subject).. sry dont know to get squared and cubed signs on here.

sry pretty long post

1. y= ax+ bx

2. y= 3x/m +2x

3. y=mx(squared)-a/b

4. y= 1/3 mx(cubed)

5. y= x/y + y/2

6. y= 1/2 mx+ kx

7. m(x-y)=3 (2x-7)

8. y=mx-abx/3

9. y= 4/x + c

10. y= x+a/x+b

luca-deltodesco

Member

Registered: 2006-05-05

Posts: 1,470

Re: rearranging formulae

1.
group like terms together, divide throughout

2.
group like terms together, divide throughout

or to make a nicer looking equation, you can do the following:

3.
move terms to LHS (left hand side) so that the squared term is on it's own, take the square root (remembeing that both -x and x are roots of x^2)

4.
again, make the cubed term be on it's own, take cubed root

(There are strictly 3 cube roots of a number, which the above will allow for, but since you'll not be introduced to complex numbers, the following would suffice)

I'll leave it at that, since I do feel i'm simply doing the work for you here

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bobbym

bumpkin

From: Bumpkinland

Registered: 2009-04-12

Posts: 109,606

Re: rearranging formulae

Hi maths noob1;

5. y= x/y + y/2

Times both sides by y:

6. y= 1/2 mx+ kx

7. m(x-y)=3 (2x-7)

8. y=mx-abx/3

or

Seeing what we have done, can you do the last 2 by yourself ? If not just holler.

Last edited by bobbym (2009-10-01 08:45:45)

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