Bonsoir,
A = (7 - 3x) (9x - 3)
A = 63x - 21 - 27x² + 9x
A = - 27x² + 72x - 21
B = (- 2 - 3y) (4 - 8y)
B = - 8 + 16y - 12y + 24y²
B = 24y² + 4y - 8
C = (4a + 6) (- 3 - 5a)
C = - 12a - 20a² - 18 - 30a
C = - 20a² - 42a - 18
D = (5z - 7) (8z + 2)
D = 40z² + 10z - 56z - 14
D = 40z² - 46z - 14