-5.4=-(0.01x^2)+.8x

Solution for -5.4=-(0.01x^2)+.8x equation:

-5.4=-(0.01x^2)+.8x

We move all terms to the left:

-5.4-(-(0.01x^2)+.8x)=0


We calculate terms in parentheses: -(-(0.01x^2)+.8x), so:

-(0.01x^2)+.8x

We add all the numbers together, and all the variables

.8x-(0.01x^2)

We get rid of parentheses

-0.01x^2+.8x

Back to the equation:

-(-0.01x^2+.8x)


We get rid of parentheses

0.01x^2-.8x-5.4=0

We add all the numbers together, and all the variables

0.01x^2-0.8x-5.4=0

a = 0.01; b = -0.8; c = -5.4;
Δ = b2-4ac
Δ = -0.82-4·0.01·(-5.4)
Δ = 0.856
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{0.856}}{2*0.01}=\frac{0.8-\sqrt{0.856}}{0.02}
$
$x_{2}=\frac{-b+\sqrt{\Delta}}{2a}=\frac{-(-0.8)+\sqrt{0.856}}{2*0.01}=\frac{0.8+\sqrt{0.856}}{0.02}
$