A= (3a + 5)x(-6a - 2) + (7a + 9)x (-a + 4)
A= -18a²-6a-30a-10-7a²+28a-9a+36
A= -25a²-17a+26
B= (2a - 1)x(9a+4) - (-6a + 7)x(-3a + 5)
B= 18a²+8a-9a-4 (18a²-30a-21a+35)
B= 18a²+8a-9a-4 (18a²-51a+35)
B= 18a²+8a-9a-4-18a²+51a-35
B= 8a-9a-4+51a-35
B= 50a-4-35
B= 50a-39
