62y+3-21y2=0

Solution for 62y+3-21y2=0 equation:

62y+3-21y^2=0

a = -21; b = 62; c = +3;
Δ = b2-4ac
Δ = 622-4·(-21)·3
Δ = 4096
The delta value is higher than zero, so the equation has two solutions
We use following formulas to calculate our solutions:
$y_{1}=\frac{-b-\sqrt{\Delta}}{2a}$
$y_{2}=\frac{-b+\sqrt{\Delta}}{2a}$

$\sqrt{\Delta}=\sqrt{4096}=64$
$y_{1}=\frac{-b-\sqrt{\Delta}}{2a}=\frac{-(62)-64}{2*-21}=\frac{-126}{-42}
=+3
$
$y_{2}=\frac{-b+\sqrt{\Delta}}{2a}=\frac{-(62)+64}{2*-21}=\frac{2}{-42}
=-1/21
$