How do you solve x^2 + 5x + 6 = 0 using the quadratic formula?

1 Answer
May 7, 2018

x = -3
x = -2

Explanation:

The quadratic formula is:

=> x = (-b +- sqrt(b^2 -4ac))/(2a)

for a quadratic of the form ax^2 + bx +c.

We have a = 1, b = 5, and c = 6.

x=(-5 +- sqrt(5^2-4(1)(6)))/(2(1))

x = (-5 +- sqrt(25-24))/(2)

x = (-5 +- sqrt(1))/(2)

x = (-5 +- 1)/(2)

Hence,

x = -6/2 = -3
and
x = -4/2 = -2

I'm not sure why you wanted to use the quadratic formula, but you could just factor the quadratic:

x^2+5x+6 = (x+3)(x+2) = 0

x+3 = 0 -> x = -3
and
x+2=0 ->x = -2