Answer:
(x - 3)(x + 1) , (x + 3)(x + 4)
Explanation:
(a)
y = x² - 2x - 3
consider the factors of the constant term (- 3) which sum to give the coefficient of the x0- term (- 2)
the factors are - 3 and + 1 , since
- 3 × + 1 = - 3 and - 3 + 1 = - 2 , then
x² - 2x - 3 = (x - 3)(x + 1)
(b)
y = x² + 7x + 12
consider the factors of the constant term (+ 12) which sum to give the coefficient of the x- term (+ 7)
the factors are + 3 and + 4 , since
3 × 4 = + 12 and 3 + 4 = + 7 , then
x² + 7x + 12 = (x + 3)(x + 4)