4/7y=28y

Solution for 4/7y=28y equation:

4/7y=28y

We move all terms to the left:

4/7y-(28y)=0


Domain of the equation: 7y!=0

y!=0/7

y!=0

y∈R


We add all the numbers together, and all the variables

-28y+4/7y=0

We multiply all the terms by the denominator


-28y*7y+4=0

Wy multiply elements

-196y^2+4=0

a = -196; b = 0; c = +4;
Δ = b2-4ac
Δ = 02-4·(-196)·4
Δ = 3136
The delta value is higher than zero, so the equation has two solutions
We use following formulas to calculate our solutions:
$y_{1}=\frac{-b-\sqrt{\Delta}}{2a}$
$y_{2}=\frac{-b+\sqrt{\Delta}}{2a}$

$\sqrt{\Delta}=\sqrt{3136}=56$
$y_{1}=\frac{-b-\sqrt{\Delta}}{2a}=\frac{-(0)-56}{2*-196}=\frac{-56}{-392}
=1/7
$
$y_{2}=\frac{-b+\sqrt{\Delta}}{2a}=\frac{-(0)+56}{2*-196}=\frac{56}{-392}
=-1/7
$