Answer:
Step-by-step explanation:
1) Sum = - 9
Product = -36
Factors = -12 , 3 {-12 + 3 = -9 & -12*3 = -36}
3a² - 9a - 12 = 3a² + 3a - 12a - 12
=3a(a + 1) - 12(a + 1)
= (a + 1) (3a - 12)
2) 4a² + 38a - 20 = 4a² + 40a - 2a - 20
=4a(a + 10) - 2(a + 10)
=(a + 10)(4a - 2)
3) 11a² + 30a - 9 = 11a² + 33a - 3a - 9
= 11a(a + 3) - 3(a + 3)
=(a + 3)(11a - 3)
