Question

Which value of x satisfies both -9x + 4y = 8 and -3x − y = 4 given the same value of y?

A.-1/7
B.-7/9
C.-8/7
D.-9
E.-4/3

Answer 1

multiply 2nd equaton by 4 and add to first

-9x+4y=8
-12x-4y=16 +
-21x+0y=24

-21x=24
divide both sides by -21
x=-24/21
x=-8/7

C is answer