Evaluation Math Example 4

Follow the full solution, then compare it with the other examples linked below.

Example 4

hard
If f(x)=x3−2xf(x) = x^3 - 2x, find f(−2)f(-2).

Solution

  1. 1
    Substitute x=−2x = -2: (−2)3−2(−2)=−8+4=−4(-2)^3 - 2(-2) = -8 + 4 = -4.
  2. 2
    Remember: (−2)3=−8(-2)^3 = -8 (odd power keeps the negative).

Answer

−4-4
Function evaluation is the same as expression evaluation—substitute and compute. Odd powers of negative numbers remain negative.

About Evaluation

The process of calculating the numerical value of a mathematical expression by substituting specific numbers for each variable and then performing the indicated operations following the order of operations (PEMDAS/BODMAS).

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More Evaluation Examples

Example 1 easy

Evaluate [formula] when [formula].

Example 2 medium

Evaluate [formula] when [formula] and [formula].

Example 3 easy

Evaluate [formula] when [formula].

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