(v+7)(8v-5)=0

Solution for (v+7)(8v-5)=0 equation:

(v+7)(8v-5)=0

We multiply parentheses ..

(+8v^2-5v+56v-35)=0

We get rid of parentheses

8v^2-5v+56v-35=0

We add all the numbers together, and all the variables

8v^2+51v-35=0

a = 8; b = 51; c = -35;
Δ = b2-4ac
Δ = 512-4·8·(-35)
Δ = 3721
The delta value is higher than zero, so the equation has two solutions
We use following formulas to calculate our solutions:
$v_{1}=\frac{-b-\sqrt{\Delta}}{2a}$
$v_{2}=\frac{-b+\sqrt{\Delta}}{2a}$

$\sqrt{\Delta}=\sqrt{3721}=61$
$v_{1}=\frac{-b-\sqrt{\Delta}}{2a}=\frac{-(51)-61}{2*8}=\frac{-112}{16}
=-7
$
$v_{2}=\frac{-b+\sqrt{\Delta}}{2a}=\frac{-(51)+61}{2*8}=\frac{10}{16}
=5/8
$