Posted by **Lucy** on Saturday, August 30, 2008 at 11:27am.

I need help-I do not understand.

The question is this: Write 2x+y=5 in polar form.

By following the example in the book I get: 5sqrt5/5=1/sqrt5*sqrt5/2. I do not know how to proceed but the answers I have to choose from are:

a) -sqrt5=r cos(theta-27 degrees)

b) sqrt5=rcos(theta-27 degrees)

c) -sqrt5=r cos(theta+27 degrees)

d)sqrt5=r cos(theta+27 degrees)

Could you please show me how to solve this problem?

Thanks