8y^2+25y-9=4y

Solution for 8y^2+25y-9=4y equation:

8y^2+25y-9=4y

We move all terms to the left:

8y^2+25y-9-(4y)=0

We add all the numbers together, and all the variables

8y^2+21y-9=0

a = 8; b = 21; c = -9;
Δ = b2-4ac
Δ = 212-4·8·(-9)
Δ = 729
The delta value is higher than zero, so the equation has two solutions
We use following formulas to calculate our solutions:
$y_{1}=\frac{-b-\sqrt{\Delta}}{2a}$
$y_{2}=\frac{-b+\sqrt{\Delta}}{2a}$

$\sqrt{\Delta}=\sqrt{729}=27$
$y_{1}=\frac{-b-\sqrt{\Delta}}{2a}=\frac{-(21)-27}{2*8}=\frac{-48}{16}
=-3
$
$y_{2}=\frac{-b+\sqrt{\Delta}}{2a}=\frac{-(21)+27}{2*8}=\frac{6}{16}
=3/8
$