(a+2)(a-3)=-4

Solution for (a+2)(a-3)=-4 equation:

(a+2)(a-3)=-4

We move all terms to the left:

(a+2)(a-3)-(-4)=0

We add all the numbers together, and all the variables

(a+2)(a-3)+4=0

We multiply parentheses ..

(+a^2-3a+2a-6)+4=0

We get rid of parentheses

a^2-3a+2a-6+4=0

We add all the numbers together, and all the variables

a^2-1a-2=0

a = 1; b = -1; c = -2;
Δ = b2-4ac
Δ = -12-4·1·(-2)
Δ = 9
The delta value is higher than zero, so the equation has two solutions
We use following formulas to calculate our solutions:
$a_{1}=\frac{-b-\sqrt{\Delta}}{2a}$
$a_{2}=\frac{-b+\sqrt{\Delta}}{2a}$

$\sqrt{\Delta}=\sqrt{9}=3$
$a_{1}=\frac{-b-\sqrt{\Delta}}{2a}=\frac{-(-1)-3}{2*1}=\frac{-2}{2}
=-1
$
$a_{2}=\frac{-b+\sqrt{\Delta}}{2a}=\frac{-(-1)+3}{2*1}=\frac{4}{2}
=2
$