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Difficulty: 3/102022 NMTC 2022 (QII-67)

If f(x-3) = 9x^2 + 2 then f(5) is ________.

Guide / Hint

Hint 1: Set the argument of the function equal to the target value: .

Hint 2: Determine what value of makes the input equal to .

Hint 3: Substitute into the expression to compute .

Solution

Step 1 (Formulate variable matching): We are given the functional equation:

We want to find the value of . To do this, we set the input argument equal to 5:

Step 2 (Solve for x):

Step 3 (Substitute x into the formula): Now we substitute into the right-hand side of the functional equation:

Step 4 (Conclusion): The value of is exactly 578.

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