(X+3)x=6

Solution for (X+3)x=6 equation:

(X+3)X=6

We move all terms to the left:

(X+3)X-(6)=0

We multiply parentheses

X^2+3X-6=0

a = 1; b = 3; c = -6;
Δ = b2-4ac
Δ = 32-4·1·(-6)
Δ = 33
The delta value is higher than zero, so the equation has two solutions
We use following formulas to calculate our solutions:
$X_{1}=\frac{-b-\sqrt{\Delta}}{2a}$
$X_{2}=\frac{-b+\sqrt{\Delta}}{2a}$

$X_{1}=\frac{-b-\sqrt{\Delta}}{2a}=\frac{-(3)-\sqrt{33}}{2*1}=\frac{-3-\sqrt{33}}{2}
$
$X_{2}=\frac{-b+\sqrt{\Delta}}{2a}=\frac{-(3)+\sqrt{33}}{2*1}=\frac{-3+\sqrt{33}}{2}
$