20(x*x)+100x=280

Solution for 20(x*x)+100x=280 equation:

20(x*x)+100x=280

We move all terms to the left:

20(x*x)+100x-(280)=0

We add all the numbers together, and all the variables

20(+x*x)+100x-280=0

We add all the numbers together, and all the variables

100x+20(+x*x)-280=0

We multiply parentheses

20x^2+100x-280=0

a = 20; b = 100; c = -280;
Δ = b2-4ac
Δ = 1002-4·20·(-280)
Δ = 32400
The delta value is higher than zero, so the equation has two solutions
We use following formulas to calculate our solutions:
$x_{1}=\frac{-b-\sqrt{\Delta}}{2a}$
$x_{2}=\frac{-b+\sqrt{\Delta}}{2a}$

$\sqrt{\Delta}=\sqrt{32400}=180$
$x_{1}=\frac{-b-\sqrt{\Delta}}{2a}=\frac{-(100)-180}{2*20}=\frac{-280}{40}
=-7
$
$x_{2}=\frac{-b+\sqrt{\Delta}}{2a}=\frac{-(100)+180}{2*20}=\frac{80}{40}
=2
$