15=3y+7/y=

Solution for 15=3y+7/y= equation:

15=3y+7/y=

We move all terms to the left:

15-(3y+7/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

-(+3y+7/y)+15=0

We get rid of parentheses

-3y-7/y+15=0

We multiply all the terms by the denominator


-3y*y+15*y-7=0

We add all the numbers together, and all the variables

15y-3y*y-7=0

Wy multiply elements

-3y^2+15y-7=0

a = -3; b = 15; c = -7;
Δ = b2-4ac
Δ = 152-4·(-3)·(-7)
Δ = 141
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{141}}{2*-3}=\frac{-15-\sqrt{141}}{-6}
$
$y_{2}=\frac{-b+\sqrt{\Delta}}{2a}=\frac{-(15)+\sqrt{141}}{2*-3}=\frac{-15+\sqrt{141}}{-6}
$