.4x2-9.63=12

Solution for .4x2-9.63=12 equation:

.4x^2-9.63=12

We move all terms to the left:

.4x^2-9.63-(12)=0

We add all the numbers together, and all the variables

.4x^2-21.63=0

a = .4; b = 0; c = -21.63;
Δ = b2-4ac
Δ = 02-4·.4·(-21.63)
Δ = 34.608
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{34.608}}{2*.4}=\frac{0-\sqrt{34.608}}{0.8}
=-\frac{\sqrt{}}{0.8}
$
$x_{2}=\frac{-b+\sqrt{\Delta}}{2a}=\frac{-(0)+\sqrt{34.608}}{2*.4}=\frac{0+\sqrt{34.608}}{0.8}
=\frac{\sqrt{}}{0.8}
$