-0.005x2+0.7x+3.5=0

Solution for -0.005x2+0.7x+3.5=0 equation:

-0.005x^2+0.7x+3.5=0

a = -0.005; b = 0.7; c = +3.5;
Δ = b2-4ac
Δ = 0.72-4·(-0.005)·3.5
Δ = 0.56
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{0.56}}{2*-0.005}=\frac{-0.7-\sqrt{0.56}}{-0.01}
$
$x_{2}=\frac{-b+\sqrt{\Delta}}{2a}=\frac{-(0.7)+\sqrt{0.56}}{2*-0.005}=\frac{-0.7+\sqrt{0.56}}{-0.01}
$