(7-v)(3v+4)=0

Solution for (7-v)(3v+4)=0 equation:

(7-v)(3v+4)=0

We add all the numbers together, and all the variables

(-1v+7)(3v+4)=0

We multiply parentheses ..

(-3v^2-4v+21v+28)=0

We get rid of parentheses

-3v^2-4v+21v+28=0

We add all the numbers together, and all the variables

-3v^2+17v+28=0

a = -3; b = 17; c = +28;
Δ = b2-4ac
Δ = 172-4·(-3)·28
Δ = 625
The delta value is higher than zero, so the equation has two solutions
We use following formulas to calculate our solutions:
$v_{1}=\frac{-b-\sqrt{\Delta}}{2a}$
$v_{2}=\frac{-b+\sqrt{\Delta}}{2a}$

$\sqrt{\Delta}=\sqrt{625}=25$
$v_{1}=\frac{-b-\sqrt{\Delta}}{2a}=\frac{-(17)-25}{2*-3}=\frac{-42}{-6}
=+7
$
$v_{2}=\frac{-b+\sqrt{\Delta}}{2a}=\frac{-(17)+25}{2*-3}=\frac{8}{-6}
=-1+1/3
$