0=-0.8x^2+150

Solution for 0=-0.8x^2+150 equation:

0=-0.8x^2+150

We move all terms to the left:

0-(-0.8x^2+150)=0

We add all the numbers together, and all the variables

-(-0.8x^2+150)=0

We get rid of parentheses

0.8x^2-150=0

a = 0.8; b = 0; c = -150;
Δ = b2-4ac
Δ = 02-4·0.8·(-150)
Δ = 480
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:

$\sqrt{\Delta}=\sqrt{480}=\sqrt{16*30}=\sqrt{16}*\sqrt{30}=4\sqrt{30}$
$x_{1}=\frac{-b-\sqrt{\Delta}}{2a}=\frac{-(0)-4\sqrt{30}}{2*0.8}=\frac{0-4\sqrt{30}}{1.6}
=-\frac{4\sqrt{30}}{1.6}
$
$x_{2}=\frac{-b+\sqrt{\Delta}}{2a}=\frac{-(0)+4\sqrt{30}}{2*0.8}=\frac{0+4\sqrt{30}}{1.6}
=\frac{4\sqrt{30}}{1.6}
$