21y-8y(2)=6y+1=10

Solution for 21y-8y(2)=6y+1=10 equation:

21y-8y(2)=6y+1=10

We move all terms to the left:

21y-8y(2)-(6y+1)=0

We add all the numbers together, and all the variables

-8y^2+21y-(6y+1)=0

We get rid of parentheses

-8y^2+21y-6y-1=0

We add all the numbers together, and all the variables

-8y^2+15y-1=0

a = -8; b = 15; c = -1;
Δ = b2-4ac
Δ = 152-4·(-8)·(-1)
Δ = 193
The delta value is higher than zero, so the equation has two solutions
We use following formulas to calculate our solutions:
$y_{1}=\frac{-b-\sqrt{\Delta}}{2a}$
$y_{2}=\frac{-b+\sqrt{\Delta}}{2a}$

$y_{1}=\frac{-b-\sqrt{\Delta}}{2a}=\frac{-(15)-\sqrt{193}}{2*-8}=\frac{-15-\sqrt{193}}{-16}
$
$y_{2}=\frac{-b+\sqrt{\Delta}}{2a}=\frac{-(15)+\sqrt{193}}{2*-8}=\frac{-15+\sqrt{193}}{-16}
$