9y^2-112y+336=0

Solution for 9y^2-112y+336=0 equation:

9y^2-112y+336=0

a = 9; b = -112; c = +336;
Δ = b2-4ac
Δ = -1122-4·9·336
Δ = 448
The delta value is higher than zero, so the equation has two solutions
We use following formulas to calculate our solutions:
$y_{1}=\frac{-b-\sqrt{\Delta}}{2a}$
$y_{2}=\frac{-b+\sqrt{\Delta}}{2a}$

The end solution:

$\sqrt{\Delta}=\sqrt{448}=\sqrt{64*7}=\sqrt{64}*\sqrt{7}=8\sqrt{7}$
$y_{1}=\frac{-b-\sqrt{\Delta}}{2a}=\frac{-(-112)-8\sqrt{7}}{2*9}=\frac{112-8\sqrt{7}}{18}
$
$y_{2}=\frac{-b+\sqrt{\Delta}}{2a}=\frac{-(-112)+8\sqrt{7}}{2*9}=\frac{112+8\sqrt{7}}{18}
$