Bonjour,
a. 2 * (3x * 3) = 2 * 9x = 18x
b. (5 * x - 2) * 8 = (5x - 2) * 8 = 40x - 16
c. (6 + 4 * x) * 2 = (6 + 4x) * 2 = 8x + 12
d. 3 + (x + 5) = 3 + x + 5 = x + 8
e. 7 * (x + 1) = 7x + 7
f. 8 (2x + 2) * 3 = (16x + 16) * 3 = 48x + 48.