Answer:
[tex]f(x) = 15 \csc(x) + 5[/tex] (first option)
Step-by-step explanation:
[tex]f(x) = a \: \csc(x) + b[/tex]
[tex]a + b = 20[/tex]
[tex] - a + b = - 10[/tex]
••••
[tex]2b = 10[/tex]
[tex]b = 5[/tex]
[tex]a = 20 - 6 = 15[/tex]
[tex] = f(x) = 15 \csc(x) + 5[/tex]
