6.3x^2-2.3x=15

Solution for 6.3x^2-2.3x=15 equation:

6.3x^2-2.3x=15

We move all terms to the left:

6.3x^2-2.3x-(15)=0

a = 6.3; b = -2.3; c = -15;
Δ = b2-4ac
Δ = -2.32-4·6.3·(-15)
Δ = 383.29
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{-(-2.3)-\sqrt{383.29}}{2*6.3}=\frac{2.3-\sqrt{383.29}}{12.6}
$
$x_{2}=\frac{-b+\sqrt{\Delta}}{2a}=\frac{-(-2.3)+\sqrt{383.29}}{2*6.3}=\frac{2.3+\sqrt{383.29}}{12.6}
$