If f(x)=2x−7f(x) = 2x-7f(x)=2x−7 and g(x)=x2+1g(x) = x^2+1g(x)=x2+1, solve (f∘g)(x)=15(f \circ g)(x) = 15(f∘g)(x)=15.
x=±2x = \pm 2x=±2
x=±3x = \pm 3x=±3
x=4x = 4x=4
x=0x = 0x=0