Question

A system of equations is shown.

Answer 1

B because tell you what you need to know ?

Answer 2

It is the only solution because 10(-6) + 6(8) = -12
-60 + 48 = -12 
-12 = -12 for the first. 
4(-6) + 2(8) = -8
-24 + 16 = -8
-8 = -8 for the second.