Question

Difficulty: EasyFunctions and Custom Symbol Operations

For the function f(x)=x25xf(x) = x^2 - 5x, what is the value of f(3)f(-3)?

  1. 24Answer
  2. B
    6
  3. C
    -6
  4. D
    -24
  5. E
    -16

Answer

24
Substituting x=3x = -3 into the function yields (3)25(3)=9+15=24(-3)^2 - 5(-3) = 9 + 15 = 24, which correctly evaluates both the exponent and linear terms following standard sign rules.

Step-by-Step Solution

1
Substitute x=3x = -3 into the function expression f(x)=x25xf(x) = x^2 - 5x.
f(3)=(3)25(3)f(-3) = (-3)^2 - 5(-3)
Function notation f(3)f(-3) requires replacing every instance of variable xx with 3-3.
2
Evaluate the exponent term (3)2(-3)^2.
9
Squaring any negative number produces a positive result: (3)×(3)=9(-3) \times (-3) = 9.
3
Evaluate the product term 5(3)-5(-3).
15
Multiplying two negative numbers yields a positive product: 5×(3)=15-5 \times (-3) = 15.
4
Sum the evaluated components.
9 + 15 = 24
Combine the results to obtain the final value of f(3)f(-3).

Key Concept

Evaluating functions with negative input values
Estimated Time:45s
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