(-2x-6)+(-1/4x-3)=90

Solution for (-2x-6)+(-1/4x-3)=90 equation:

(-2x-6)+(-1/4x-3)=90

We move all terms to the left:

(-2x-6)+(-1/4x-3)-(90)=0


Domain of the equation: 4x-3)!=0

x∈R


We get rid of parentheses

-2x-1/4x-6-3-90=0

We multiply all the terms by the denominator


-2x*4x-6*4x-3*4x-90*4x-1=0

Wy multiply elements

-8x^2-24x-12x-360x-1=0

We add all the numbers together, and all the variables

-8x^2-396x-1=0

a = -8; b = -396; c = -1;
Δ = b2-4ac
Δ = -3962-4·(-8)·(-1)
Δ = 156784
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:

$\sqrt{\Delta}=\sqrt{156784}=\sqrt{16*9799}=\sqrt{16}*\sqrt{9799}=4\sqrt{9799}$
$x_{1}=\frac{-b-\sqrt{\Delta}}{2a}=\frac{-(-396)-4\sqrt{9799}}{2*-8}=\frac{396-4\sqrt{9799}}{-16}
$
$x_{2}=\frac{-b+\sqrt{\Delta}}{2a}=\frac{-(-396)+4\sqrt{9799}}{2*-8}=\frac{396+4\sqrt{9799}}{-16}
$