If f(x) = 2x - 5 and g(x) = 7x^2, what is f(g(2))?

  f(g(2)) = 51

Step-by-step explanation:

The expression f(g(2)) means you are to use g(2) as the argument for the function f(x).

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The value of a function is found by substituting the argument value in the defining expression, then simplifying the result.

Here, we do that in steps, working outward from the innermost parentheses, as required by the Order of Operations.

  g(2) = 7(2^2) = 7·4 = 28 . . . . . put 2 where x is in g(x) = 7x^2, evaluate

  f(g(2)) = f(28) = 2(28) -5 = 56 -5 = 51 . . . . . . put 28 where x is in f(x) = 2x -5

  f(g(2)) = 51

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Many graphing calculators will let you define functions. You can use the calculator to compute the value for you. A spreadsheet can do the same thing.