Question

Solve the system for x and y.

-8x-y= -43
8x-5y= -71

A. ( 4,11)
B. (3,19)
C. (-2,11)
D. ( 2,27)

Answer 1

Answer=B(3,19)

`- 8x - y = - 43 \\ - y = - 43 +8x \\ y = 43 - 8x \\ \\ 8x - 5(43 - 8x) = - 71 \\ 8x - 215 + 40x = - 71 \\ 8x + 40x = - 71 + 215 \\ 48 x = 144 \\ x = 3 \\ - 8(3) - y = - 43 \\ - 24 - y = - 43 \\ - y = - 43 + 24 \\ - y = - 19 \\ y = 19`

Answer 2

B x=3 ,y=19

Explanation:

make y subject of the formula from the 1st equation y= 43-8x

then substitute the above equation on the 2nd equation 8x-5y= -71 and solve fr x

8x - 5(43-8x) = -71

8x-215+48x= -71

48x=-71+215

48x=144

x=3

and

y= 43-8x

y=43-8(3)

y=19

(3,19)