4/5y=y

Solution for 4/5y=y equation:

4/5y=y

We move all terms to the left:

4/5y-(y)=0


Domain of the equation: 5y!=0

y!=0/5

y!=0

y∈R


We add all the numbers together, and all the variables

-1y+4/5y=0

We multiply all the terms by the denominator


-1y*5y+4=0

Wy multiply elements

-5y^2+4=0

a = -5; b = 0; c = +4;
Δ = b2-4ac
Δ = 02-4·(-5)·4
Δ = 80
The delta value is higher than zero, so the equation has two solutions
We use following formulas to calculate our solutions:
$y_{1}=\frac{-b-\sqrt{\Delta}}{2a}$
$y_{2}=\frac{-b+\sqrt{\Delta}}{2a}$

The end solution:

$\sqrt{\Delta}=\sqrt{80}=\sqrt{16*5}=\sqrt{16}*\sqrt{5}=4\sqrt{5}$
$y_{1}=\frac{-b-\sqrt{\Delta}}{2a}=\frac{-(0)-4\sqrt{5}}{2*-5}=\frac{0-4\sqrt{5}}{-10}
=-\frac{4\sqrt{5}}{-10}
=-\frac{2\sqrt{5}}{-5}
$
$y_{2}=\frac{-b+\sqrt{\Delta}}{2a}=\frac{-(0)+4\sqrt{5}}{2*-5}=\frac{0+4\sqrt{5}}{-10}
=\frac{4\sqrt{5}}{-10}
=\frac{2\sqrt{5}}{-5}
$