-x^2+25x-144=0

Solution for -x^2+25x-144=0 equation:

-x^2+25x-144=0

We add all the numbers together, and all the variables

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