Hi, I have to rearrange the formula to get a and b on their own. The real answers are different to mine:

p(a + b) = q (a-b) [a]

pa + pb = qa - qb

pa-qa = -qb - pb

a (p-q) = -qb - pb

a = (-qb - pb)/(p-q)

(qb + pb)/(q -p)

it's differnet to mine!!!!!!

And finding rearranging to get b is

p(a + b) = q (a-b) [a]

pa + pb = qa - qb

pa-qa = -qb - pb

pb + qb = qa - pa

b(p + q) = qa - pa

b = (qa - pa)/(p + q)

(pa + pa)/(q + p)

Errrrrr!

Can someone so me where i went wrong

Thanks

Last edited:

hage567
Homework Helper
It's not that your answers are wrong, I think they are done properly. They just don't look exactly the same. For "a", I think that perhaps if you multiplied through by -1 after a(p-q)=-qb-pb, and arranged it based on that, your answer would turn out looking the same as the "real answer". To check, you can plug numbers into the equations and see if they turn out the same.
For "b", just change the order of p and q, it's addition anyway so it won't change anything.

mjsd
Homework Helper
(-qb - pb)/(p-q) is equivalent to (qb + pb)/(q -p) just multiply top and bottom by -1.

for the second one you have may a misprint... check what you have typed