The given equation is expressed as
x^2 + 7x + 12
This is a quadratic equation. We would solve by applying the method of factorisation. The first step is to multiply x^2 with 12. It becomes 12x^2. We would find two terms such that their sum or difference is 7x and their product is 12x^2. The terms are 4x and 3x. By replacing 7x with 4x + 3x, we have
x^2 + 4x + 3x + 12 = 0
We would factorise by grouping. The groups are (x^2 + 4x) and (3x + 12). It becomes
x(x + 4) + 3(x + 4) = 0
Since x + 4 is common, it becomes
(x + 4)(x + 3) = 0
x + 4 = 0 or x + 3 = 0
x = - 4 or x = - 3