(3u+5)(2u-8)=0

Solution for (3u+5)(2u-8)=0 equation:

(3u+5)(2u-8)=0

We multiply parentheses ..

(+6u^2-24u+10u-40)=0

We get rid of parentheses

6u^2-24u+10u-40=0

We add all the numbers together, and all the variables

6u^2-14u-40=0

a = 6; b = -14; c = -40;
Δ = b2-4ac
Δ = -142-4·6·(-40)
Δ = 1156
The delta value is higher than zero, so the equation has two solutions
We use following formulas to calculate our solutions:
$u_{1}=\frac{-b-\sqrt{\Delta}}{2a}$
$u_{2}=\frac{-b+\sqrt{\Delta}}{2a}$

$\sqrt{\Delta}=\sqrt{1156}=34$
$u_{1}=\frac{-b-\sqrt{\Delta}}{2a}=\frac{-(-14)-34}{2*6}=\frac{-20}{12}
=-1+2/3
$
$u_{2}=\frac{-b+\sqrt{\Delta}}{2a}=\frac{-(-14)+34}{2*6}=\frac{48}{12}
=4
$