Given: x2 + 5x + 6 = 0.
On splitting the middle term 5x as 3x + 2x, we get:
x2 + 3x + 2x + 6 = 0
=> x(x + 3) + 2(x + 3) = 0
=> (x + 3) (x + 2) = 0
We know that if the product of two numbers is zero, then at least one of them must be zero.
Thus,
x + 3 = 0 or x + 2 = 0
=> x = –3 or x = –2
Therefore, the solution of the given equation is x = –3, –2.