(2x-14)(x-28)=0

Solution for (2x-14)(x-28)=0 equation:

(2x-14)(x-28)=0

We multiply parentheses ..

(+2x^2-56x-14x+392)=0

We get rid of parentheses

2x^2-56x-14x+392=0

We add all the numbers together, and all the variables

2x^2-70x+392=0

a = 2; b = -70; c = +392;
Δ = b2-4ac
Δ = -702-4·2·392
Δ = 1764
The delta value is higher than zero, so the equation has two solutions
We use following formulas to calculate our solutions:
$x_{1}=\frac{-b-\sqrt{\Delta}}{2a}$
$x_{2}=\frac{-b+\sqrt{\Delta}}{2a}$

$\sqrt{\Delta}=\sqrt{1764}=42$
$x_{1}=\frac{-b-\sqrt{\Delta}}{2a}=\frac{-(-70)-42}{2*2}=\frac{28}{4}
=7
$
$x_{2}=\frac{-b+\sqrt{\Delta}}{2a}=\frac{-(-70)+42}{2*2}=\frac{112}{4}
=28
$