(1-v)(5v-7)=0

Solution for (1-v)(5v-7)=0 equation:

(1-v)(5v-7)=0

We add all the numbers together, and all the variables

(-1v+1)(5v-7)=0

We multiply parentheses ..

(-5v^2+7v+5v-7)=0

We get rid of parentheses

-5v^2+7v+5v-7=0

We add all the numbers together, and all the variables

-5v^2+12v-7=0

a = -5; b = 12; c = -7;
Δ = b2-4ac
Δ = 122-4·(-5)·(-7)
Δ = 4
The delta value is higher than zero, so the equation has two solutions
We use following formulas to calculate our solutions:
$v_{1}=\frac{-b-\sqrt{\Delta}}{2a}$
$v_{2}=\frac{-b+\sqrt{\Delta}}{2a}$

$\sqrt{\Delta}=\sqrt{4}=2$
$v_{1}=\frac{-b-\sqrt{\Delta}}{2a}=\frac{-(12)-2}{2*-5}=\frac{-14}{-10}
=1+2/5
$
$v_{2}=\frac{-b+\sqrt{\Delta}}{2a}=\frac{-(12)+2}{2*-5}=\frac{-10}{-10}
=1
$