0=-0.05(x^2-26x-120)

Solution for 0=-0.05(x^2-26x-120) equation:

0=-0.05(x^2-26x-120)

We move all terms to the left:

0-(-0.05(x^2-26x-120))=0

We add all the numbers together, and all the variables

-(-0.05(x^2-26x-120))=0


We calculate terms in parentheses: -(-0.05(x^2-26x-120)), so:

-0.05(x^2-26x-120)

We multiply parentheses

-0.05x^2+1.3x+6

Back to the equation:

-(-0.05x^2+1.3x+6)


We get rid of parentheses

0.05x^2-1.3x-6=0

a = 0.05; b = -1.3; c = -6;
Δ = b2-4ac
Δ = -1.32-4·0.05·(-6)
Δ = 2.89
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{-(-1.3)-\sqrt{2.89}}{2*0.05}=\frac{1.3-\sqrt{2.89}}{0.1}
$
$x_{2}=\frac{-b+\sqrt{\Delta}}{2a}=\frac{-(-1.3)+\sqrt{2.89}}{2*0.05}=\frac{1.3+\sqrt{2.89}}{0.1}
$