0.25x2-x-8=0

Solution for 0.25x2-x-8=0 equation:

0.25x^2-x-8=0

We add all the numbers together, and all the variables

0.25x^2-1x-8=0

a = 0.25; b = -1; c = -8;
Δ = b2-4ac
Δ = -12-4·0.25·(-8)
Δ = 9
The delta value is higher than zero, so the equation has two solutions
We use following formulas to calculate our solutions:
$x_{1}=\frac{-b-\sqrt{\Delta}}{2a}$
$x_{2}=\frac{-b+\sqrt{\Delta}}{2a}$

$\sqrt{\Delta}=\sqrt{9}=3$
$x_{1}=\frac{-b-\sqrt{\Delta}}{2a}=\frac{-(-1)-3}{2*0.25}=\frac{-2}{0.5}
=-4
$
$x_{2}=\frac{-b+\sqrt{\Delta}}{2a}=\frac{-(-1)+3}{2*0.25}=\frac{4}{0.5}
=8
$