4x^2+30x=87.75

Solution for 4x^2+30x=87.75 equation:

4x^2+30x=87.75

We move all terms to the left:

4x^2+30x-(87.75)=0

We add all the numbers together, and all the variables

4x^2+30x-87.75=0

a = 4; b = 30; c = -87.75;
Δ = b2-4ac
Δ = 302-4·4·(-87.75)
Δ = 2304
The delta value is higher than zero, so the equation has two solutions
We use following formulas to calculate our solutions:
$x_{1}=\frac{-b-\sqrt{\Delta}}{2a}$
$x_{2}=\frac{-b+\sqrt{\Delta}}{2a}$

$\sqrt{\Delta}=\sqrt{2304}=48$
$x_{1}=\frac{-b-\sqrt{\Delta}}{2a}=\frac{-(30)-48}{2*4}=\frac{-78}{8}
=-9+3/4
$
$x_{2}=\frac{-b+\sqrt{\Delta}}{2a}=\frac{-(30)+48}{2*4}=\frac{18}{8}
=2+1/4
$