Answer:
A. 7.5
Explanation:
15 / -6 +x = 10
15 /-6 +x * (-6+x) = 10 * (-6+x ) : multiply both sides by -6+x
15 = 10(-6+x) : simplify
15 = -60+10x : distribute
15+60 = 10x : addition property of equality
75/10=10x/10 : division property of equality
x = 7.5