(9+u)(2u-7)=0

Solution for (9+u)(2u-7)=0 equation:

(9+u)(2u-7)=0

We add all the numbers together, and all the variables

(u+9)(2u-7)=0

We multiply parentheses ..

(+2u^2-7u+18u-63)=0

We get rid of parentheses

2u^2-7u+18u-63=0

We add all the numbers together, and all the variables

2u^2+11u-63=0

a = 2; b = 11; c = -63;
Δ = b2-4ac
Δ = 112-4·2·(-63)
Δ = 625
The delta value is higher than zero, so the equation has two solutions
We use following formulas to calculate our solutions:
$u_{1}=\frac{-b-\sqrt{\Delta}}{2a}$
$u_{2}=\frac{-b+\sqrt{\Delta}}{2a}$

$\sqrt{\Delta}=\sqrt{625}=25$
$u_{1}=\frac{-b-\sqrt{\Delta}}{2a}=\frac{-(11)-25}{2*2}=\frac{-36}{4}
=-9
$
$u_{2}=\frac{-b+\sqrt{\Delta}}{2a}=\frac{-(11)+25}{2*2}=\frac{14}{4}
=3+1/2
$