using substitution.
7x-8y=112 and y=-2x+9
2007-08-30 15:54:22 · 4 answers · asked by Anonymous in Education & Reference ➔ Homework Help
7x-8(-2x+9)=112
7x+16x-72=112
23x-72=112
23x=184
X=8
y=-2(8)+9
y=-5
(8, -5) should be the final answer.
2007-08-30 16:00:25 · answer #1 · answered by Jennifer L. 4 · 0⤊ 0⤋
7x - 8y = 112 and y = -2x + 9 substitute (9 - 2x) for y in first eq.
7x - 8(9 - 2x) = 112 remove brackets
7x - 72 + 16x = 112 collect like terms
23x = 184
therefore x = 8
now substitute this in either eq. I'll let you do that for yourself.
2007-08-30 23:01:03 · answer #2 · answered by jemhasb 7 · 0⤊ 0⤋
Looks like algebra to me. Too bad I don't have a pencil...
2007-08-30 22:57:52 · answer #3 · answered by Bryce 7 · 0⤊ 1⤋
by using math. duh!. ok. in order to do this problem u need to add 8y to both sides for the first problem. and thats all i can tell u right now.
2007-08-30 23:00:18 · answer #4 · answered by Mn Guy =) 3 · 0⤊ 1⤋