(1-u)(2u+9)=0

Solution for (1-u)(2u+9)=0 equation:

(1-u)(2u+9)=0

We add all the numbers together, and all the variables

(-1u+1)(2u+9)=0

We multiply parentheses ..

(-2u^2-9u+2u+9)=0

We get rid of parentheses

-2u^2-9u+2u+9=0

We add all the numbers together, and all the variables

-2u^2-7u+9=0

a = -2; b = -7; c = +9;
Δ = b2-4ac
Δ = -72-4·(-2)·9
Δ = 121
The delta value is higher than zero, so the equation has two solutions
We use following formulas to calculate our solutions:
$u_{1}=\frac{-b-\sqrt{\Delta}}{2a}$
$u_{2}=\frac{-b+\sqrt{\Delta}}{2a}$

$\sqrt{\Delta}=\sqrt{121}=11$
$u_{1}=\frac{-b-\sqrt{\Delta}}{2a}=\frac{-(-7)-11}{2*-2}=\frac{-4}{-4}
=1
$
$u_{2}=\frac{-b+\sqrt{\Delta}}{2a}=\frac{-(-7)+11}{2*-2}=\frac{18}{-4}
=-4+1/2
$