7a - 8y=112 y=2a+9 i keep getting a= 8 and y= -7?

2 ⤊

2007-10-02 16:27:09 · 4 answers · asked by cow man 1 in Science & Mathematics ➔ Mathematics

7a - 8 (2a + 9) = 112
7a - 16a - 72 = 112
- 9a = 184
a = - 184/9

y = - 368/9 + 81/9
y = - 287/9

2007-10-02 20:10:40 · answer #1 · answered by Como 7 · 2⤊ 0⤋

y=(112-7a)/-8
y=-14+(.875a)
y=2a+9

2a+9 = -14+.875a
a = -20.444
y = -31.888

2007-10-02 23:53:30 · answer #2 · answered by doober 1 · 0⤊ 0⤋

it all works except the y=2a+9 bit

2007-10-02 23:34:25 · answer #3 · answered by ♥ 4 · 0⤊ 0⤋

that's a hard algebra question.

2007-10-02 23:30:09 · answer #4 · answered by ? 6 · 0⤊ 0⤋