Multiply first equation by 7.
49r - 63s = 84
Multiply second equation by 9.
81r + 63s = 864
Subtract first equation from second.
32r = 780
r = 780/ 32 = 24 3/8
Put value in either equation to solve for s.
7(780/32) - 9s = 12
5460/32 - 9s = 12
-9s = 12 - 5460/32 = (384-5460)/32 = -5076/32
Divide both sides by -9.
s = 5076/(32 * 9) = 5076/288 = 17 5/8
I hope this helps.
I need help!
Solve by the elimination method:
7r-9s=-12
9r+7s=96
When I do this, I get a crazy fraction, and I know the answer is a point. (r,s) But what I'm getting is ridiculous. I got -564/130=s! That has to be totally wrong!
1 answer
1 answer