# Quick Maths Q

#### Seft

Soldato
In a textbook of mine, there's a step which I can't get my head around.

B*E*X = A*(Y - E*X)

rearranges to

X = [A/(A+B)](Y/E)

I can't figure out how to do it. Could anyone walk me through it?

Thanks

p.s. Bonus points for knowing what the last equation is (A and B would normally be alpha and beta)

BEX=A(Y-EX)
BEX=AY-AEX
X(BE+AE)=AY
X=(AY)/(BE+AE)=YA/(E(B+A))=(A/(A+B))(Y/E)

Just like any rearrangement, get all the terms containing the X on one side, take X out and you're there.

(I don't recognise the equation, except possibly from GCSE electronics. Might be entirely off the mark there! What are you studying at what level?)

edit, ignore

awesome thanks

omg what happened to the no homework rule?

VeNT said:
omg what happened to the no homework rule?

That's a rule? Ooops

Anyway, I think the OP is older than compulsary school level, it's just a little (easy) step, I doubt I'm ruining anyone's education!

This isn't homework. Appendix 8 in the third edition of Microeconomics by Jeffrey Perloff, if you must know.

I've got an exam tomorrow

PinkPig said:
That's a rule? Ooops

Anyway, I think the OP is older than compulsary school level, it's just a little (easy) step, I doubt I'm ruining anyone's education!
iirc it was never written into the FAQ but there was a period where we where getting about 2-3 of these a night from some of the younger members, people started putting in wrong answers to mess with them and stuff.

Seft said:
This isn't homework. Appendix 8 in the third edition of Microeconomics by Jeffrey Perloff, if you must know.

I've got an exam tomorrow

Good luck - my IB exams start tomorrow too! Good old English literature exam at 8am in the morning