2z^2-1,7z-1=0

Solution for 2z^2-1,7z-1=0 equation:

2z^2-1.7z-1=0

a = 2; b = -1.7; c = -1;
Δ = b2-4ac
Δ = -1.72-4·2·(-1)
Δ = 10.89
The delta value is higher than zero, so the equation has two solutions
We use following formulas to calculate our solutions:
$z_{1}=\frac{-b-\sqrt{\Delta}}{2a}$
$z_{2}=\frac{-b+\sqrt{\Delta}}{2a}$

$z_{1}=\frac{-b-\sqrt{\Delta}}{2a}=\frac{-(-1.7)-\sqrt{10.89}}{2*2}=\frac{1.7-\sqrt{10.89}}{4}
$
$z_{2}=\frac{-b+\sqrt{\Delta}}{2a}=\frac{-(-1.7)+\sqrt{10.89}}{2*2}=\frac{1.7+\sqrt{10.89}}{4}
$