(9v+7)(v+7)=0

Solution for (9v+7)(v+7)=0 equation:

(9v+7)(v+7)=0

We multiply parentheses ..

(+9v^2+63v+7v+49)=0

We get rid of parentheses

9v^2+63v+7v+49=0

We add all the numbers together, and all the variables

9v^2+70v+49=0

a = 9; b = 70; c = +49;
Δ = b2-4ac
Δ = 702-4·9·49
Δ = 3136
The delta value is higher than zero, so the equation has two solutions
We use following formulas to calculate our solutions:
$v_{1}=\frac{-b-\sqrt{\Delta}}{2a}$
$v_{2}=\frac{-b+\sqrt{\Delta}}{2a}$

$\sqrt{\Delta}=\sqrt{3136}=56$
$v_{1}=\frac{-b-\sqrt{\Delta}}{2a}=\frac{-(70)-56}{2*9}=\frac{-126}{18}
=-7
$
$v_{2}=\frac{-b+\sqrt{\Delta}}{2a}=\frac{-(70)+56}{2*9}=\frac{-14}{18}
=-7/9
$