5x^2+8x-1=4

Solution for 5x^2+8x-1=4 equation:

5x^2+8x-1=4

We move all terms to the left:

5x^2+8x-1-(4)=0

We add all the numbers together, and all the variables

5x^2+8x-5=0

a = 5; b = 8; c = -5;
Δ = b2-4ac
Δ = 82-4·5·(-5)
Δ = 164
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:

$\sqrt{\Delta}=\sqrt{164}=\sqrt{4*41}=\sqrt{4}*\sqrt{41}=2\sqrt{41}$
$x_{1}=\frac{-b-\sqrt{\Delta}}{2a}=\frac{-(8)-2\sqrt{41}}{2*5}=\frac{-8-2\sqrt{41}}{10}
$
$x_{2}=\frac{-b+\sqrt{\Delta}}{2a}=\frac{-(8)+2\sqrt{41}}{2*5}=\frac{-8+2\sqrt{41}}{10}
$