0.06x^2-9x=-320

Solution for 0.06x^2-9x=-320 equation:

0.06x^2-9x=-320

We move all terms to the left:

0.06x^2-9x-(-320)=0

We add all the numbers together, and all the variables

0.06x^2-9x+320=0

a = 0.06; b = -9; c = +320;
Δ = b2-4ac
Δ = -92-4·0.06·320
Δ = 4.2
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{-(-9)-\sqrt{4.2}}{2*0.06}=\frac{9-\sqrt{4.2}}{0.12}
$
$x_{2}=\frac{-b+\sqrt{\Delta}}{2a}=\frac{-(-9)+\sqrt{4.2}}{2*0.06}=\frac{9+\sqrt{4.2}}{0.12}
$