3x=x2-20

Solution for 3x=x2-20 equation:

3x=x2-20

We move all terms to the left:

3x-(x2-20)=0

We add all the numbers together, and all the variables

-(+x^2-20)+3x=0

We get rid of parentheses

-x^2+3x+20=0

We add all the numbers together, and all the variables

-1x^2+3x+20=0

a = -1; b = 3; c = +20;
Δ = b2-4ac
Δ = 32-4·(-1)·20
Δ = 89
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{89}}{2*-1}=\frac{-3-\sqrt{89}}{-2}
$
$x_{2}=\frac{-b+\sqrt{\Delta}}{2a}=\frac{-(3)+\sqrt{89}}{2*-1}=\frac{-3+\sqrt{89}}{-2}
$