180=28+(25x-10)(15x+2)

Solution for 180=28+(25x-10)(15x+2) equation:

180=28+(25x-10)(15x+2)

We move all terms to the left:

180-(28+(25x-10)(15x+2))=0

We multiply parentheses ..

-(28+(+375x^2+50x-150x-20))+180=0


We calculate terms in parentheses: -(28+(+375x^2+50x-150x-20)), so:

28+(+375x^2+50x-150x-20)

determiningTheFunctionDomain
(+375x^2+50x-150x-20)+28

We get rid of parentheses

375x^2+50x-150x-20+28

We add all the numbers together, and all the variables

375x^2-100x+8

Back to the equation:

-(375x^2-100x+8)


We get rid of parentheses

-375x^2+100x-8+180=0

We add all the numbers together, and all the variables

-375x^2+100x+172=0

a = -375; b = 100; c = +172;
Δ = b2-4ac
Δ = 1002-4·(-375)·172
Δ = 268000
The delta value is higher than zero, so the equation has two solutions
We use following formulas to calculate our solutions:
$x_{1}=\frac{-b-\sqrt{\Delta}}{2a}$
$x_{2}=\frac{-b+\sqrt{\Delta}}{2a}$

The end solution:

$\sqrt{\Delta}=\sqrt{268000}=\sqrt{400*670}=\sqrt{400}*\sqrt{670}=20\sqrt{670}$
$x_{1}=\frac{-b-\sqrt{\Delta}}{2a}=\frac{-(100)-20\sqrt{670}}{2*-375}=\frac{-100-20\sqrt{670}}{-750}
$
$x_{2}=\frac{-b+\sqrt{\Delta}}{2a}=\frac{-(100)+20\sqrt{670}}{2*-375}=\frac{-100+20\sqrt{670}}{-750}
$