(50+3x)x=50

Solution for (50+3x)x=50 equation:

(50+3x)x=50

We move all terms to the left:

(50+3x)x-(50)=0

We add all the numbers together, and all the variables

(3x+50)x-50=0

We multiply parentheses

3x^2+50x-50=0

a = 3; b = 50; c = -50;
Δ = b2-4ac
Δ = 502-4·3·(-50)
Δ = 3100
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:

$\sqrt{\Delta}=\sqrt{3100}=\sqrt{100*31}=\sqrt{100}*\sqrt{31}=10\sqrt{31}$
$x_{1}=\frac{-b-\sqrt{\Delta}}{2a}=\frac{-(50)-10\sqrt{31}}{2*3}=\frac{-50-10\sqrt{31}}{6}
$
$x_{2}=\frac{-b+\sqrt{\Delta}}{2a}=\frac{-(50)+10\sqrt{31}}{2*3}=\frac{-50+10\sqrt{31}}{6}
$