Determine whether the equation defines y as a linear functio

Determine whether the equation defines y as a linear function of x.

it wont let me connect the equation bcuz of the radical so here is the eqution - 4 radical x +15y=o

Yes or No     

If so, write it in the form

y = mx + b.

(If an answer does not exist, enter DNE.)
y =  

Solution

-4 sqrt(x +15y) =0

dividing both sides by -4

sqrt(x+15y)=0

squaring both sides

x+15y=0

15y =x

y=(1/15) x +0

which is of the form y=mx +b

And as we can see that, here y is a function of x .