x^2+6x=24

2 answers

x^2 +6x+9=24+9
(X+3)^2=33
x+3=sqrt(33)
x=+-sqrt(33)-3

or look up Quadratic formula
looks like it does not factor, so...
in this case I would complete the square.

x^2 + 6x + 9 = 24 + 9
(x+3)^2 = 33
x+3 = ± √ 33
x = -3 ± √33

If a quadratic does not factor and the first term is
1x^2 with an even number as the x coefficient, completing the square is faster than using the formula. Secondly, completing the square gives you the simplified answer, whereas with the formula you still have to simplify the final answer.
Try it by using the formula for the above to get the same answer