Example

Evaluating the Polynomial Function f(x)=3x2+2x−15f(x) = 3x^2 + 2x - 15

To evaluate the polynomial function f(x)=3x2+2x−15f(x) = 3x^2 + 2x - 15 for specific values, substitute the value for the variable xx and simplify using the order of operations:

  • Evaluate f(3)f(3): Substitute 33 for xx to obtain f(3)=3(3)2+2(3)−15f(3) = 3(3)^2 + 2(3) - 15. Simplifying the exponent gives 3(9)+6−153(9) + 6 - 15. Multiply to get 27+6−1527 + 6 - 15, and simplify to find f(3)=18f(3) = 18.
  • Evaluate f(−5)f(-5): Substitute −5-5 for xx to obtain f(−5)=3(−5)2+2(−5)−15f(-5) = 3(-5)^2 + 2(-5) - 15. Simplifying the exponent gives 3(25)−10−153(25) - 10 - 15. Multiply to get 75−10−1575 - 10 - 15, and simplify to find f(−5)=50f(-5) = 50.
  • Evaluate f(0)f(0): Substitute 00 for xx to obtain f(0)=3(0)2+2(0)−15f(0) = 3(0)^2 + 2(0) - 15. Simplifying the exponent gives 3(0)+0−153(0) + 0 - 15, which simplifies to f(0)=−15f(0) = -15.

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Updated 2026-06-17

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