7x^2-1+20x-4+15x+17=180

Solution for 7x^2-1+20x-4+15x+17=180 equation:

7x^2-1+20x-4+15x+17=180

We move all terms to the left:

7x^2-1+20x-4+15x+17-(180)=0

We add all the numbers together, and all the variables

7x^2+35x-168=0

a = 7; b = 35; c = -168;
Δ = b2-4ac
Δ = 352-4·7·(-168)
Δ = 5929
The delta value is higher than zero, so the equation has two solutions
We use following formulas to calculate our solutions:
$x_{1}=\frac{-b-\sqrt{\Delta}}{2a}$
$x_{2}=\frac{-b+\sqrt{\Delta}}{2a}$

$\sqrt{\Delta}=\sqrt{5929}=77$
$x_{1}=\frac{-b-\sqrt{\Delta}}{2a}=\frac{-(35)-77}{2*7}=\frac{-112}{14}
=-8
$
$x_{2}=\frac{-b+\sqrt{\Delta}}{2a}=\frac{-(35)+77}{2*7}=\frac{42}{14}
=3
$