15.42=(3.14*x)*x

Solution for 15.42=(3.14*x)*x equation:

15.42=(3.14x)*x

We move all terms to the left:

15.42-((3.14x)*x)=0

We add all the numbers together, and all the variables

-((+3.14x)*x)+15.42=0


We calculate terms in parentheses: -((+3.14x)*x), so:

(+3.14x)*x

We multiply parentheses

3x^2

Back to the equation:

-(3x^2)


a = -3; b = 0; c = +15.42;
Δ = b2-4ac
Δ = 02-4·(-3)·15.42
Δ = 185.04
The delta value is higher than zero, so the equation has two solutions
We use following formulas to calculate our solutions:
$x_{1}=\frac{-b-\sqrt{\Delta}}{2a}$
$x_{2}=\frac{-b+\sqrt{\Delta}}{2a}$

$x_{1}=\frac{-b-\sqrt{\Delta}}{2a}=\frac{-(0)-\sqrt{185.04}}{2*-3}=\frac{0-\sqrt{185.04}}{-6}
=-\frac{\sqrt{}}{-6}
$
$x_{2}=\frac{-b+\sqrt{\Delta}}{2a}=\frac{-(0)+\sqrt{185.04}}{2*-3}=\frac{0+\sqrt{185.04}}{-6}
=\frac{\sqrt{}}{-6}
$