3+1/4*cos(theta)=13/4

Question

Please help really confused.
I was given the answer as 1
but how do I figure it out. I know you are suppose to subtract 3 from both sides but how do i do that with the 13/4?

Answer 1

3+1/4*cos(theta)=13/4
1/4*cos(theta)=13/4 - 3 = 1/4
cos(theta)= 1
we know cos 0 = 1
so Ø = 0