4x^2+5x-1=15

Solution for 4x^2+5x-1=15 equation:

4x^2+5x-1=15

We move all terms to the left:

4x^2+5x-1-(15)=0

We add all the numbers together, and all the variables

4x^2+5x-16=0

a = 4; b = 5; c = -16;
Δ = b2-4ac
Δ = 52-4·4·(-16)
Δ = 281
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{281}}{2*4}=\frac{-5-\sqrt{281}}{8}
$
$x_{2}=\frac{-b+\sqrt{\Delta}}{2a}=\frac{-(5)+\sqrt{281}}{2*4}=\frac{-5+\sqrt{281}}{8}
$