5x^2-0.8x=10

Solution for 5x^2-0.8x=10 equation:

5x^2-0.8x=10

We move all terms to the left:

5x^2-0.8x-(10)=0

a = 5; b = -0.8; c = -10;
Δ = b2-4ac
Δ = -0.82-4·5·(-10)
Δ = 200.64
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{-(-0.8)-\sqrt{200.64}}{2*5}=\frac{0.8-\sqrt{200.64}}{10}
$
$x_{2}=\frac{-b+\sqrt{\Delta}}{2a}=\frac{-(-0.8)+\sqrt{200.64}}{2*5}=\frac{0.8+\sqrt{200.64}}{10}
$