(u+4)(u-2)=-5

Solution for (u+4)(u-2)=-5 equation:

(u+4)(u-2)=-5

We move all terms to the left:

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

We add all the numbers together, and all the variables

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

We multiply parentheses ..

(+u^2-2u+4u-8)+5=0

We get rid of parentheses

u^2-2u+4u-8+5=0

We add all the numbers together, and all the variables

u^2+2u-3=0

a = 1; b = 2; c = -3;
Δ = b2-4ac
Δ = 22-4·1·(-3)
Δ = 16
The delta value is higher than zero, so the equation has two solutions
We use following formulas to calculate our solutions:
$u_{1}=\frac{-b-\sqrt{\Delta}}{2a}$
$u_{2}=\frac{-b+\sqrt{\Delta}}{2a}$

$\sqrt{\Delta}=\sqrt{16}=4$
$u_{1}=\frac{-b-\sqrt{\Delta}}{2a}=\frac{-(2)-4}{2*1}=\frac{-6}{2}
=-3
$
$u_{2}=\frac{-b+\sqrt{\Delta}}{2a}=\frac{-(2)+4}{2*1}=\frac{2}{2}
=1
$