Step-by-step explanation:
when you do an arithmetic operation to functions, you do it for the defining expressions.
so,
(f+g)(x) = (x + 3) + (4x + 4) = x + 3 + 4x + 4 = 5x + 7
(f*g)(x) = (x+3)*(4x+4) = 4x² + 12x + 4x + 12 = 4x² + 16x + 12
= 4(x² + 4x + 3)
(f-g)(4) = (4+3) - (4×4+4) = 7 - (16+4) = 7 - 20 = -13
