2x(70+2x)=600

Solution for 2x(70+2x)=600 equation:

2x(70+2x)=600

We move all terms to the left:

2x(70+2x)-(600)=0

We add all the numbers together, and all the variables

2x(2x+70)-600=0

We multiply parentheses

4x^2+140x-600=0

a = 4; b = 140; c = -600;
Δ = b2-4ac
Δ = 1402-4·4·(-600)
Δ = 29200
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:

$\sqrt{\Delta}=\sqrt{29200}=\sqrt{400*73}=\sqrt{400}*\sqrt{73}=20\sqrt{73}$
$x_{1}=\frac{-b-\sqrt{\Delta}}{2a}=\frac{-(140)-20\sqrt{73}}{2*4}=\frac{-140-20\sqrt{73}}{8}
$
$x_{2}=\frac{-b+\sqrt{\Delta}}{2a}=\frac{-(140)+20\sqrt{73}}{2*4}=\frac{-140+20\sqrt{73}}{8}
$