(8u+1)(9u+2)=0

Solution for (8u+1)(9u+2)=0 equation:

(8u+1)(9u+2)=0

We multiply parentheses ..

(+72u^2+16u+9u+2)=0

We get rid of parentheses

72u^2+16u+9u+2=0

We add all the numbers together, and all the variables

72u^2+25u+2=0

a = 72; b = 25; c = +2;
Δ = b2-4ac
Δ = 252-4·72·2
Δ = 49
The delta value is higher than zero, so the equation has two solutions
We use following formulas to calculate our solutions:
$u_{1}=\frac{-b-\sqrt{\Delta}}{2a}$
$u_{2}=\frac{-b+\sqrt{\Delta}}{2a}$

$\sqrt{\Delta}=\sqrt{49}=7$
$u_{1}=\frac{-b-\sqrt{\Delta}}{2a}=\frac{-(25)-7}{2*72}=\frac{-32}{144}
=-2/9
$
$u_{2}=\frac{-b+\sqrt{\Delta}}{2a}=\frac{-(25)+7}{2*72}=\frac{-18}{144}
=-1/8
$