15u^2-18u-35=0

Solution for 15u^2-18u-35=0 equation:

15u^2-18u-35=0

a = 15; b = -18; c = -35;
Δ = b2-4ac
Δ = -182-4·15·(-35)
Δ = 2424
The delta value is higher than zero, so the equation has two solutions
We use following formulas to calculate our solutions:
$u_{1}=\frac{-b-\sqrt{\Delta}}{2a}$
$u_{2}=\frac{-b+\sqrt{\Delta}}{2a}$

The end solution:

$\sqrt{\Delta}=\sqrt{2424}=\sqrt{4*606}=\sqrt{4}*\sqrt{606}=2\sqrt{606}$
$u_{1}=\frac{-b-\sqrt{\Delta}}{2a}=\frac{-(-18)-2\sqrt{606}}{2*15}=\frac{18-2\sqrt{606}}{30}
$
$u_{2}=\frac{-b+\sqrt{\Delta}}{2a}=\frac{-(-18)+2\sqrt{606}}{2*15}=\frac{18+2\sqrt{606}}{30}
$