8x^2-0.4x=0

Solution for 8x^2-0.4x=0 equation:

8x^2-0.4x=0

a = 8; b = -0.4; c = 0;
Δ = b2-4ac
Δ = -0.42-4·8·0
Δ = 0.16
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{-(-0.4)-\sqrt{0.16}}{2*8}=\frac{0.4-\sqrt{0.16}}{16}
$
$x_{2}=\frac{-b+\sqrt{\Delta}}{2a}=\frac{-(-0.4)+\sqrt{0.16}}{2*8}=\frac{0.4+\sqrt{0.16}}{16}
$