Answer:
x = - 7, x = - 5
Explanation:
To factorise the quadratic
Consider the factors of the constant term (+ 35) which sum to give the coefficient of the x- term (+ 12)
The factors are + 7 and + 5, since
7 × 5 = 35 and 7 + 5 = 12, hence
x² + 12x + 35 = 0 ← in standard form
(x + 7)(x + 5) = 0 ← in factored form
Equate each factor to zero and solve for x
x + 7 = 0 ⇒ x = - 7
x + 5 = 0 ⇒ x = - 5