Answer:
x = - 4, x = 7
Step-by-step explanation:
Given
x(x - 3) = 28 ← distribute left side
x² - 3x = 28 ← subtract 28 from both sides
x² - 3x - 28 = 0 ← in standard form
To factor the quadratic
Consider the factors of the constant term (- 28) which sum to give the coefficient of the x- term (- 3)
The factors are - 7 and + 4, since
- 7 × 4 = - 28 and - 7 + 4 = - 3, hence
(x - 7)(x + 4) = 0
Equate each factor to zero and solve for x
x - 7 = 0 ⇒ x = 7
x + 4 = 0 ⇒ x = - 4
