x^2+10x+20=7

Solution for x^2+10x+20=7 equation:

x^2+10x+20=7

We move all terms to the left:

x^2+10x+20-(7)=0

We add all the numbers together, and all the variables

x^2+10x+13=0

a = 1; b = 10; c = +13;
Δ = b2-4ac
Δ = 102-4·1·13
Δ = 48
The delta value is higher than zero, so the equation has two solutions
We use following formulas to calculate our solutions:
$x_{1}=\frac{-b-\sqrt{\Delta}}{2a}$
$x_{2}=\frac{-b+\sqrt{\Delta}}{2a}$

The end solution:

$\sqrt{\Delta}=\sqrt{48}=\sqrt{16*3}=\sqrt{16}*\sqrt{3}=4\sqrt{3}$
$x_{1}=\frac{-b-\sqrt{\Delta}}{2a}=\frac{-(10)-4\sqrt{3}}{2*1}=\frac{-10-4\sqrt{3}}{2}
$
$x_{2}=\frac{-b+\sqrt{\Delta}}{2a}=\frac{-(10)+4\sqrt{3}}{2*1}=\frac{-10+4\sqrt{3}}{2}
$