(5u-3)(5+u)=0

Solution for (5u-3)(5+u)=0 equation:

(5u-3)(5+u)=0

We add all the numbers together, and all the variables

(5u-3)(u+5)=0

We multiply parentheses ..

(+5u^2+25u-3u-15)=0

We get rid of parentheses

5u^2+25u-3u-15=0

We add all the numbers together, and all the variables

5u^2+22u-15=0

a = 5; b = 22; c = -15;
Δ = b2-4ac
Δ = 222-4·5·(-15)
Δ = 784
The delta value is higher than zero, so the equation has two solutions
We use following formulas to calculate our solutions:
$u_{1}=\frac{-b-\sqrt{\Delta}}{2a}$
$u_{2}=\frac{-b+\sqrt{\Delta}}{2a}$

$\sqrt{\Delta}=\sqrt{784}=28$
$u_{1}=\frac{-b-\sqrt{\Delta}}{2a}=\frac{-(22)-28}{2*5}=\frac{-50}{10}
=-5
$
$u_{2}=\frac{-b+\sqrt{\Delta}}{2a}=\frac{-(22)+28}{2*5}=\frac{6}{10}
=3/5
$