0.35x^2-3.5x-9=0

Solution for 0.35x^2-3.5x-9=0 equation:

0.35x^2-3.5x-9=0

a = 0.35; b = -3.5; c = -9;
Δ = b2-4ac
Δ = -3.52-4·0.35·(-9)
Δ = 24.85
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{-(-3.5)-\sqrt{24.85}}{2*0.35}=\frac{3.5-\sqrt{24.85}}{0.7}
$
$x_{2}=\frac{-b+\sqrt{\Delta}}{2a}=\frac{-(-3.5)+\sqrt{24.85}}{2*0.35}=\frac{3.5+\sqrt{24.85}}{0.7}
$