(X+3)*(x+3)=10

Solution for (X+3)*(x+3)=10 equation:

(X+3)(X+3)=10

We move all terms to the left:

(X+3)(X+3)-(10)=0

We multiply parentheses ..

(+X^2+3X+3X+9)-10=0

We get rid of parentheses

X^2+3X+3X+9-10=0

We add all the numbers together, and all the variables

X^2+6X-1=0

a = 1; b = 6; c = -1;
Δ = b2-4ac
Δ = 62-4·1·(-1)
Δ = 40
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:

$\sqrt{\Delta}=\sqrt{40}=\sqrt{4*10}=\sqrt{4}*\sqrt{10}=2\sqrt{10}$
$X_{1}=\frac{-b-\sqrt{\Delta}}{2a}=\frac{-(6)-2\sqrt{10}}{2*1}=\frac{-6-2\sqrt{10}}{2}
$
$X_{2}=\frac{-b+\sqrt{\Delta}}{2a}=\frac{-(6)+2\sqrt{10}}{2*1}=\frac{-6+2\sqrt{10}}{2}
$