.2(x+22)(x-15)=0

Solution for .2(x+22)(x-15)=0 equation:

.2(x+22)(x-15)=0

We multiply parentheses ..

.2(+x^2-15x+22x-330)=0

We multiply parentheses

0.2x^2-3x+4.4x-66=0

We add all the numbers together, and all the variables

0.2x^2+1.4x-66=0

a = 0.2; b = 1.4; c = -66;
Δ = b2-4ac
Δ = 1.42-4·0.2·(-66)
Δ = 54.76
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{-(1.4)-\sqrt{54.76}}{2*0.2}=\frac{-1.4-\sqrt{54.76}}{0.4}
$
$x_{2}=\frac{-b+\sqrt{\Delta}}{2a}=\frac{-(1.4)+\sqrt{54.76}}{2*0.2}=\frac{-1.4+\sqrt{54.76}}{0.4}
$