solve by the elimination method
7r-8s=55
8r+7s=79

Question

hero · Answer

What the...?

hero · Answer

I know I helped you with this before

hero · Answer

What happened?

anonymous · Answer

I only solved for r

hero · Answer

to solve for s, replace what you found for r into the equation

anonymous · Answer

multiply first line by 8 and second line by -7. Sum both.

56r -64s=440
-56r -49s=-553
----------------
0 -113s=-113

s=1

subst on first line:

r=9

anonymous · Answer

Thanks Leo , that was crystal clear.

hero · Answer

Yeah, but...

anonymous · Answer

the squeaky wheel gets the greese, and other army maxims....

hero · Answer

Leo's method doesn't allow you to play with the numbers as much

anonymous · Answer

Hero, i solve by elimination method... i eliminate the r and found s.

hero · Answer

I eliminated s and found r.

hero · Answer

You do realize that r comes before s. You're supposed to find that first.

hero · Answer

Think x and y

anonymous · Answer

its the same!

hero · Answer

Not really. A true mathematician follow the correct order and procedure of things.

hero · Answer

If I was your teacher I would take a quarter of a point off for each wrong step

anonymous · Answer

ok. Im not 'true mathematician'. Im engineer.. i solve problems. =)

anonymous · Answer

You right.

hero · Answer

If you're an engineer, I hope you're following the instructions in the right order.