375=40x-x^2

Solution for 375=40x-x^2 equation:

375=40x-x^2

We move all terms to the left:

375-(40x-x^2)=0

We get rid of parentheses

x^2-40x+375=0

a = 1; b = -40; c = +375;
Δ = b2-4ac
Δ = -402-4·1·375
Δ = 100
The delta value is higher than zero, so the equation has two solutions
We use following formulas to calculate our solutions:
$x_{1}=\frac{-b-\sqrt{\Delta}}{2a}$
$x_{2}=\frac{-b+\sqrt{\Delta}}{2a}$

$\sqrt{\Delta}=\sqrt{100}=10$
$x_{1}=\frac{-b-\sqrt{\Delta}}{2a}=\frac{-(-40)-10}{2*1}=\frac{30}{2}
=15
$
$x_{2}=\frac{-b+\sqrt{\Delta}}{2a}=\frac{-(-40)+10}{2*1}=\frac{50}{2}
=25
$