Does anyone know how to solve this??

a) (f + g)(x) = x² - 2x + 3x - 4 = x² + x - 4

domain: x E R

b) (f - h)(x) = x² - 2x - ( - 2x + 1) = x² - 1

domain: x E R

c) (f.g)(x) = (x² - 2x)(3x - 4) = 3x³ - 10x² + 8x

domain: x E R

d)

domain: x E R\{0; 2}