(7x-2)(-2x+8)=0

Solution for (7x-2)(-2x+8)=0 equation:

(7x-2)(-2x+8)=0

We multiply parentheses ..

(-14x^2+56x+4x-16)=0

We get rid of parentheses

-14x^2+56x+4x-16=0

We add all the numbers together, and all the variables

-14x^2+60x-16=0

a = -14; b = 60; c = -16;
Δ = b2-4ac
Δ = 602-4·(-14)·(-16)
Δ = 2704
The delta value is higher than zero, so the equation has two solutions
We use following formulas to calculate our solutions:
$x_{1}=\frac{-b-\sqrt{\Delta}}{2a}$
$x_{2}=\frac{-b+\sqrt{\Delta}}{2a}$

$\sqrt{\Delta}=\sqrt{2704}=52$
$x_{1}=\frac{-b-\sqrt{\Delta}}{2a}=\frac{-(60)-52}{2*-14}=\frac{-112}{-28}
=+4
$
$x_{2}=\frac{-b+\sqrt{\Delta}}{2a}=\frac{-(60)+52}{2*-14}=\frac{-8}{-28}
=2/7
$