2y^2-21y+10=0

Solution for 2y^2-21y+10=0 equation:

2y^2-21y+10=0

a = 2; b = -21; c = +10;
Δ = b2-4ac
Δ = -212-4·2·10
Δ = 361
The delta value is higher than zero, so the equation has two solutions
We use following formulas to calculate our solutions:
$y_{1}=\frac{-b-\sqrt{\Delta}}{2a}$
$y_{2}=\frac{-b+\sqrt{\Delta}}{2a}$

$\sqrt{\Delta}=\sqrt{361}=19$
$y_{1}=\frac{-b-\sqrt{\Delta}}{2a}=\frac{-(-21)-19}{2*2}=\frac{2}{4}
=1/2
$
$y_{2}=\frac{-b+\sqrt{\Delta}}{2a}=\frac{-(-21)+19}{2*2}=\frac{40}{4}
=10
$