Answer:
x = - 4 or x = 7
Step-by-step explanation:
The given equation is expressed as
x^2 - 3x - 28 = 0
This is a quadratic equation. We would solve by applying the method of factorization. The first step is to multiply x^2 with - 28. It becomes – 28x^2. We would find two terms such that their sum or difference is - 3x and their product is 28x^2. The terms are 4x and – 7x. By replacing - 3x with 4x - 7x, we have
x^2 + 4x - 7x - 28 = 0
We would factorize by grouping. It becomes
x(x + 4) - 7(x + 4) = 0
(x + 4)(x - 7) = 0
x + 4 = 0 or x - 7 = 0
x = - 4 or x = 7