I'm not sure how to solve this. I could really use your help!! I would really appreciate it if u explain if to me as simple as possible.Thanks !!

f(x) = 6x+5

The notation f(a) is short for f(x=a). Similarly, f(2a) is f(x=2a). So just replace the x in the function with a or 2a:

f(x) = 6x + 5

f(a) = 6a + 5

f(2a) = 6(2a) + 5 = 12a + 5

So:

f(a) + f(2a) = 6a + 5 + 12a + 5

Combine like terms to get the answer.

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