Using linear functions, it is found that:
A linear function for a cost depending on the number of movies x is given by:
[tex]C(x) = C(0) + ax[/tex]
In which:
For Plan A, $33 per month plus $3 per movie watched, hence [tex]C(0) = 33, a = 3[/tex], and the equation is:
[tex]C_a(x) = 33 + 3x[/tex]
For Plan B, $37 per month plus $2 per movie watched, hence [tex]C(0) = 37, a = 2[/tex], and the equation is:
[tex]C_b(x) = 37 + 2x[/tex]
The monthly cost is equal when:
[tex]C_a(x) = C_b(x)[/tex]
[tex]33 + 3x = 37 + 2x[/tex]
[tex]x = 4[/tex]
The monthly plans would have an equal cost when 4 movies are watched.
A similar problem is given at https://brainly.com/question/16302622