60=25x-0.2x^2

Solution for 60=25x-0.2x^2 equation:

60=25x-0.2x^2

We move all terms to the left:

60-(25x-0.2x^2)=0

We get rid of parentheses

0.2x^2-25x+60=0

a = 0.2; b = -25; c = +60;
Δ = b2-4ac
Δ = -252-4·0.2·60
Δ = 577
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{-(-25)-\sqrt{577}}{2*0.2}=\frac{25-\sqrt{577}}{0.4}
$
$x_{2}=\frac{-b+\sqrt{\Delta}}{2a}=\frac{-(-25)+\sqrt{577}}{2*0.2}=\frac{25+\sqrt{577}}{0.4}
$