2y+4=720/y

Solution for 2y+4=720/y equation:

2y+4=720/y

We move all terms to the left:

2y+4-(720/y)=0


Domain of the equation: y)!=0

y!=0/1

y!=0

y∈R


We add all the numbers together, and all the variables

2y-(+720/y)+4=0

We get rid of parentheses

2y-720/y+4=0

We multiply all the terms by the denominator


2y*y+4*y-720=0

We add all the numbers together, and all the variables

4y+2y*y-720=0

Wy multiply elements

2y^2+4y-720=0

a = 2; b = 4; c = -720;
Δ = b2-4ac
Δ = 42-4·2·(-720)
Δ = 5776
The delta value is higher than zero, so the equation has two solutions
We use following formulas to calculate our solutions:
$y_{1}=\frac{-b-\sqrt{\Delta}}{2a}$
$y_{2}=\frac{-b+\sqrt{\Delta}}{2a}$

$\sqrt{\Delta}=\sqrt{5776}=76$
$y_{1}=\frac{-b-\sqrt{\Delta}}{2a}=\frac{-(4)-76}{2*2}=\frac{-80}{4}
=-20
$
$y_{2}=\frac{-b+\sqrt{\Delta}}{2a}=\frac{-(4)+76}{2*2}=\frac{72}{4}
=18
$