0=-0.01x^2+0.7x+6.2

Solution for 0=-0.01x^2+0.7x+6.2 equation:

0=-0.01x^2+0.7x+6.2

We move all terms to the left:

0-(-0.01x^2+0.7x+6.2)=0

We add all the numbers together, and all the variables

-(-0.01x^2+0.7x+6.2)=0

We get rid of parentheses

0.01x^2-0.7x-6.2=0

a = 0.01; b = -0.7; c = -6.2;
Δ = b2-4ac
Δ = -0.72-4·0.01·(-6.2)
Δ = 0.738
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{-(-0.7)-\sqrt{0.738}}{2*0.01}=\frac{0.7-\sqrt{0.738}}{0.02}
$
$x_{2}=\frac{-b+\sqrt{\Delta}}{2a}=\frac{-(-0.7)+\sqrt{0.738}}{2*0.01}=\frac{0.7+\sqrt{0.738}}{0.02}
$