7=-0.005x^2+1.25x+10

Solution for 7=-0.005x^2+1.25x+10 equation:

7=-0.005x^2+1.25x+10

We move all terms to the left:

7-(-0.005x^2+1.25x+10)=0

We get rid of parentheses

0.005x^2-1.25x-10+7=0

We add all the numbers together, and all the variables

0.005x^2-1.25x-3=0

a = 0.005; b = -1.25; c = -3;
Δ = b2-4ac
Δ = -1.252-4·0.005·(-3)
Δ = 1.6225
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{-(-1.25)-\sqrt{1.6225}}{2*0.005}=\frac{1.25-\sqrt{1.6225}}{0.01}
$
$x_{2}=\frac{-b+\sqrt{\Delta}}{2a}=\frac{-(-1.25)+\sqrt{1.6225}}{2*0.005}=\frac{1.25+\sqrt{1.6225}}{0.01}
$