(X+2)(x+5)=4

Solution for (X+2)(x+5)=4 equation:

(X+2)(X+5)=4

We move all terms to the left:

(X+2)(X+5)-(4)=0

We multiply parentheses ..

(+X^2+5X+2X+10)-4=0

We get rid of parentheses

X^2+5X+2X+10-4=0

We add all the numbers together, and all the variables

X^2+7X+6=0

a = 1; b = 7; c = +6;
Δ = b2-4ac
Δ = 72-4·1·6
Δ = 25
The delta value is higher than zero, so the equation has two solutions
We use following formulas to calculate our solutions:
$X_{1}=\frac{-b-\sqrt{\Delta}}{2a}$
$X_{2}=\frac{-b+\sqrt{\Delta}}{2a}$

$\sqrt{\Delta}=\sqrt{25}=5$
$X_{1}=\frac{-b-\sqrt{\Delta}}{2a}=\frac{-(7)-5}{2*1}=\frac{-12}{2}
=-6
$
$X_{2}=\frac{-b+\sqrt{\Delta}}{2a}=\frac{-(7)+5}{2*1}=\frac{-2}{2}
=-1
$