-3y^2-7y+4.25=0

Solution for -3y^2-7y+4.25=0 equation:

-3y^2-7y+4.25=0

a = -3; b = -7; c = +4.25;
Δ = b2-4ac
Δ = -72-4·(-3)·4.25
Δ = 100
The delta value is higher than zero, so the equation has two solutions
We use following formulas to calculate our solutions:
$y_{1}=\frac{-b-\sqrt{\Delta}}{2a}$
$y_{2}=\frac{-b+\sqrt{\Delta}}{2a}$

$\sqrt{\Delta}=\sqrt{100}=10$
$y_{1}=\frac{-b-\sqrt{\Delta}}{2a}=\frac{-(-7)-10}{2*-3}=\frac{-3}{-6}
=1/2
$
$y_{2}=\frac{-b+\sqrt{\Delta}}{2a}=\frac{-(-7)+10}{2*-3}=\frac{17}{-6}
=-2+5/6
$