3.5x^2-9.8x+4=0

Solution for 3.5x^2-9.8x+4=0 equation:

3.5x^2-9.8x+4=0

a = 3.5; b = -9.8; c = +4;
Δ = b2-4ac
Δ = -9.82-4·3.5·4
Δ = 40.04
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{-(-9.8)-\sqrt{40.04}}{2*3.5}=\frac{9.8-\sqrt{40.04}}{7}
$
$x_{2}=\frac{-b+\sqrt{\Delta}}{2a}=\frac{-(-9.8)+\sqrt{40.04}}{2*3.5}=\frac{9.8+\sqrt{40.04}}{7}
$