How to solve f (x) = x^2+1, g (x) = 5x how to solve

(f + g) (x) = f (x) + g (x) = [3x + 2] + [4 - 5x] = 3x - 5x + 2 + 4 = - 2x + 6 (f - g) (x) = f (x) - g (x) = [3x + 2] - [4 - 5x] = 3x + 5x + 2 - 4 = 8x - 2 (f*g) (x) = [f (x) ][g (x) ] = (3x + 2) (4 - 5x) = 12x + 8 - 15x2 - 10x = - 15x2 + 2 x + 8