2u^2+18u-30=0

Solution for 2u^2+18u-30=0 equation:

2u^2+18u-30=0

a = 2; b = 18; c = -30;
Δ = b2-4ac
Δ = 182-4·2·(-30)
Δ = 564
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:

$\sqrt{\Delta}=\sqrt{564}=\sqrt{4*141}=\sqrt{4}*\sqrt{141}=2\sqrt{141}$
$u_{1}=\frac{-b-\sqrt{\Delta}}{2a}=\frac{-(18)-2\sqrt{141}}{2*2}=\frac{-18-2\sqrt{141}}{4}
$
$u_{2}=\frac{-b+\sqrt{\Delta}}{2a}=\frac{-(18)+2\sqrt{141}}{2*2}=\frac{-18+2\sqrt{141}}{4}
$