Explanation:
(f+g)(x) means we just add the 2 functions, so we have
(x-3) + 2x² = 2x² + x - 3
(f-g)(x) means we subtract g(x) from f(x), so we have
(x-3) - (2x²) = -2x²+x-3
Assuming that the dot signifies a multiplication sign and not a composition sign, we have
(f*g)(x) = f(x) * g(x)
= (x-3) * 2x²
= 2x³ - 6x²
Plugging -2 in, we get
2(-2)³-6(-2)² = -16 -24 = -40