If

2x - y = 3
x + y = 1
compute 8x - 7y.

Please help!

1 answer

adding the equations (to cancel y) ... 3 x = 4 ... x = 4/3

4/3 + y = 1 ... y = -1/3

8 x - 7 y = 8(4/3) - 7(-1/3) = 32/3 + 7/3 = ?