2x(x+14)=40

Solution for 2x(x+14)=40 equation:

2x(x+14)=40

We move all terms to the left:

2x(x+14)-(40)=0

We multiply parentheses

2x^2+28x-40=0

a = 2; b = 28; c = -40;
Δ = b2-4ac
Δ = 282-4·2·(-40)
Δ = 1104
The delta value is higher than zero, so the equation has two solutions
We use following formulas to calculate our solutions:
$x_{1}=\frac{-b-\sqrt{\Delta}}{2a}$
$x_{2}=\frac{-b+\sqrt{\Delta}}{2a}$

The end solution:

$\sqrt{\Delta}=\sqrt{1104}=\sqrt{16*69}=\sqrt{16}*\sqrt{69}=4\sqrt{69}$
$x_{1}=\frac{-b-\sqrt{\Delta}}{2a}=\frac{-(28)-4\sqrt{69}}{2*2}=\frac{-28-4\sqrt{69}}{4}
$
$x_{2}=\frac{-b+\sqrt{\Delta}}{2a}=\frac{-(28)+4\sqrt{69}}{2*2}=\frac{-28+4\sqrt{69}}{4}
$