144=x(25-x)

Solution for 144=x(25-x) equation:

144=x(25-x)

We move all terms to the left:

144-(x(25-x))=0

We add all the numbers together, and all the variables

-(x(-1x+25))+144=0


We calculate terms in parentheses: -(x(-1x+25)), so:

x(-1x+25)

We multiply parentheses

-1x^2+25x

Back to the equation:

-(-1x^2+25x)


We get rid of parentheses

1x^2-25x+144=0

We add all the numbers together, and all the variables

x^2-25x+144=0

a = 1; b = -25; c = +144;
Δ = b2-4ac
Δ = -252-4·1·144
Δ = 49
The delta value is higher than zero, so the equation has two solutions
We use following formulas to calculate our solutions:
$x_{1}=\frac{-b-\sqrt{\Delta}}{2a}$
$x_{2}=\frac{-b+\sqrt{\Delta}}{2a}$

$\sqrt{\Delta}=\sqrt{49}=7$
$x_{1}=\frac{-b-\sqrt{\Delta}}{2a}=\frac{-(-25)-7}{2*1}=\frac{18}{2}
=9
$
$x_{2}=\frac{-b+\sqrt{\Delta}}{2a}=\frac{-(-25)+7}{2*1}=\frac{32}{2}
=16
$