2x*2x-5x-4=0

Solution for 2x*2x-5x-4=0 equation:

2x*2x-5x-4=0

We add all the numbers together, and all the variables

-5x+2x*2x-4=0

Wy multiply elements

4x^2-5x-4=0

a = 4; b = -5; c = -4;
Δ = b2-4ac
Δ = -52-4·4·(-4)
Δ = 89
The delta value is higher than zero, so the equation has two solutions
We use following formulas to calculate our solutions:
$x_{1}=\frac{-b-\sqrt{\Delta}}{2a}$
$x_{2}=\frac{-b+\sqrt{\Delta}}{2a}$

$x_{1}=\frac{-b-\sqrt{\Delta}}{2a}=\frac{-(-5)-\sqrt{89}}{2*4}=\frac{5-\sqrt{89}}{8}
$
$x_{2}=\frac{-b+\sqrt{\Delta}}{2a}=\frac{-(-5)+\sqrt{89}}{2*4}=\frac{5+\sqrt{89}}{8}
$