2x(x-4)=714

Solution for 2x(x-4)=714 equation:

2x(x-4)=714

We move all terms to the left:

2x(x-4)-(714)=0

We multiply parentheses

2x^2-8x-714=0

a = 2; b = -8; c = -714;
Δ = b2-4ac
Δ = -82-4·2·(-714)
Δ = 5776
The delta value is higher than zero, so the equation has two solutions
We use following formulas to calculate our solutions:
$x_{1}=\frac{-b-\sqrt{\Delta}}{2a}$
$x_{2}=\frac{-b+\sqrt{\Delta}}{2a}$

$\sqrt{\Delta}=\sqrt{5776}=76$
$x_{1}=\frac{-b-\sqrt{\Delta}}{2a}=\frac{-(-8)-76}{2*2}=\frac{-68}{4}
=-17
$
$x_{2}=\frac{-b+\sqrt{\Delta}}{2a}=\frac{-(-8)+76}{2*2}=\frac{84}{4}
=21
$