(25+2x)(-9x+72)=0

Solution for (25+2x)(-9x+72)=0 equation:

(25+2x)(-9x+72)=0

We add all the numbers together, and all the variables

(2x+25)(-9x+72)=0

We multiply parentheses ..

(-18x^2+144x-225x+1800)=0

We get rid of parentheses

-18x^2+144x-225x+1800=0

We add all the numbers together, and all the variables

-18x^2-81x+1800=0

a = -18; b = -81; c = +1800;
Δ = b2-4ac
Δ = -812-4·(-18)·1800
Δ = 136161
The delta value is higher than zero, so the equation has two solutions
We use following formulas to calculate our solutions:
$x_{1}=\frac{-b-\sqrt{\Delta}}{2a}$
$x_{2}=\frac{-b+\sqrt{\Delta}}{2a}$

$\sqrt{\Delta}=\sqrt{136161}=369$
$x_{1}=\frac{-b-\sqrt{\Delta}}{2a}=\frac{-(-81)-369}{2*-18}=\frac{-288}{-36}
=+8
$
$x_{2}=\frac{-b+\sqrt{\Delta}}{2a}=\frac{-(-81)+369}{2*-18}=\frac{450}{-36}
=-12+1/2
$