3.14*(x*x)=50

Solution for 3.14*(x*x)=50 equation:

3.14(x*x)=50

We move all terms to the left:

3.14(x*x)-(50)=0

We add all the numbers together, and all the variables

3.14(+x*x)-50=0

We multiply parentheses

3.14x^2-50=0

a = 3.14; b = 0; c = -50;
Δ = b2-4ac
Δ = 02-4·3.14·(-50)
Δ = 628
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:

$\sqrt{\Delta}=\sqrt{628}=\sqrt{4*157}=\sqrt{4}*\sqrt{157}=2\sqrt{157}$
$x_{1}=\frac{-b-\sqrt{\Delta}}{2a}=\frac{-(0)-2\sqrt{157}}{2*3.14}=\frac{0-2\sqrt{157}}{6.28}
=-\frac{2\sqrt{157}}{6.28}
=-\frac{\sqrt{157}}{3.14}
$
$x_{2}=\frac{-b+\sqrt{\Delta}}{2a}=\frac{-(0)+2\sqrt{157}}{2*3.14}=\frac{0+2\sqrt{157}}{6.28}
=\frac{2\sqrt{157}}{6.28}
=\frac{\sqrt{157}}{3.14}
$