(X+1)(x+4)=4

Solution for (X+1)(x+4)=4 equation:

(X+1)(X+4)=4

We move all terms to the left:

(X+1)(X+4)-(4)=0

We multiply parentheses ..

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

We get rid of parentheses

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

We add all the numbers together, and all the variables

X^2+5X=0

a = 1; b = 5; c = 0;
Δ = b2-4ac
Δ = 52-4·1·0
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{-(5)-5}{2*1}=\frac{-10}{2}
=-5
$
$X_{2}=\frac{-b+\sqrt{\Delta}}{2a}=\frac{-(5)+5}{2*1}=\frac{0}{2}
=0
$