(1+u)(5u+-8)=0

Solution for (1+u)(5u+-8)=0 equation:

(1+u)(5u+-8)=0

We add all the numbers together, and all the variables

(u+1)(5u-8)=0

We multiply parentheses ..

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

We get rid of parentheses

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

We add all the numbers together, and all the variables

5u^2-3u-8=0

a = 5; b = -3; c = -8;
Δ = b2-4ac
Δ = -32-4·5·(-8)
Δ = 169
The delta value is higher than zero, so the equation has two solutions
We use following formulas to calculate our solutions:
$u_{1}=\frac{-b-\sqrt{\Delta}}{2a}$
$u_{2}=\frac{-b+\sqrt{\Delta}}{2a}$

$\sqrt{\Delta}=\sqrt{169}=13$
$u_{1}=\frac{-b-\sqrt{\Delta}}{2a}=\frac{-(-3)-13}{2*5}=\frac{-10}{10}
=-1
$
$u_{2}=\frac{-b+\sqrt{\Delta}}{2a}=\frac{-(-3)+13}{2*5}=\frac{16}{10}
=1+3/5
$