0=3.2x2+0.7x-12

Solution for 0=3.2x2+0.7x-12 equation:

0=3.2x^2+0.7x-12

We move all terms to the left:

0-(3.2x^2+0.7x-12)=0

We add all the numbers together, and all the variables

-(3.2x^2+0.7x-12)=0

We get rid of parentheses

-3.2x^2-0.7x+12=0

a = -3.2; b = -0.7; c = +12;
Δ = b2-4ac
Δ = -0.72-4·(-3.2)·12
Δ = 154.09
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{-(-0.7)-\sqrt{154.09}}{2*-3.2}=\frac{0.7-\sqrt{154.09}}{-6.4}
$
$x_{2}=\frac{-b+\sqrt{\Delta}}{2a}=\frac{-(-0.7)+\sqrt{154.09}}{2*-3.2}=\frac{0.7+\sqrt{154.09}}{-6.4}
$