4x+x^2=-2+9x-x^2

Solution for 4x+x^2=-2+9x-x^2 equation:

4x+x^2=-2+9x-x^2

We move all terms to the left:

4x+x^2-(-2+9x-x^2)=0

We get rid of parentheses

x^2+x^2-9x+4x+2=0

We add all the numbers together, and all the variables

2x^2-5x+2=0

a = 2; b = -5; c = +2;
Δ = b2-4ac
Δ = -52-4·2·2
Δ = 9
The delta value is higher than zero, so the equation has two solutions
We use following formulas to calculate our solutions:
$x_{1}=\frac{-b-\sqrt{\Delta}}{2a}$
$x_{2}=\frac{-b+\sqrt{\Delta}}{2a}$

$\sqrt{\Delta}=\sqrt{9}=3$
$x_{1}=\frac{-b-\sqrt{\Delta}}{2a}=\frac{-(-5)-3}{2*2}=\frac{2}{4}
=1/2
$
$x_{2}=\frac{-b+\sqrt{\Delta}}{2a}=\frac{-(-5)+3}{2*2}=\frac{8}{4}
=2
$