4x^2+66-90=0

Solution for 4x^2+66-90=0 equation:

4x^2+66-90=0

We add all the numbers together, and all the variables

4x^2-24=0

a = 4; b = 0; c = -24;
Δ = b2-4ac
Δ = 02-4·4·(-24)
Δ = 384
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:

$\sqrt{\Delta}=\sqrt{384}=\sqrt{64*6}=\sqrt{64}*\sqrt{6}=8\sqrt{6}$
$x_{1}=\frac{-b-\sqrt{\Delta}}{2a}=\frac{-(0)-8\sqrt{6}}{2*4}=\frac{0-8\sqrt{6}}{8}
=-\frac{8\sqrt{6}}{8}
=-\sqrt{6}
$
$x_{2}=\frac{-b+\sqrt{\Delta}}{2a}=\frac{-(0)+8\sqrt{6}}{2*4}=\frac{0+8\sqrt{6}}{8}
=\frac{8\sqrt{6}}{8}
=\sqrt{6}
$