Math Problem Statement

(h - 2f)(5), where h(x) = x^2 - 1 and f(x) = -x + 1. Find each value.

Solution

We are tasked with evaluating (h2f)(5)(h - 2f)(5) given the functions:

  • h(x)=x21h(x) = x^2 - 1
  • f(x)=x+1f(x) = -x + 1.

Let’s solve step by step:

Step 1: Expand (h2f)(x)(h - 2f)(x)

We know: (h2f)(x)=h(x)2f(x).(h - 2f)(x) = h(x) - 2f(x).

Step 2: Plug in x=5x = 5

We need to evaluate: (h2f)(5)=h(5)2f(5).(h - 2f)(5) = h(5) - 2f(5).

Step 3: Calculate h(5)h(5)

Substitute x=5x = 5 into h(x)=x21h(x) = x^2 - 1: h(5)=521=251=24.h(5) = 5^2 - 1 = 25 - 1 = 24.

Step 4: Calculate f(5)f(5)

Substitute x=5x = 5 into f(x)=x+1f(x) = -x + 1: f(5)=(5)+1=5+1=4.f(5) = -(5) + 1 = -5 + 1 = -4.

Step 5: Calculate 2f(5)2f(5)

Multiply f(5)f(5) by 2: 2f(5)=2(4)=8.2f(5) = 2(-4) = -8.

Step 6: Combine results

Now substitute into (h2f)(5)=h(5)2f(5)(h - 2f)(5) = h(5) - 2f(5): (h2f)(5)=24(8)=24+8=32.(h - 2f)(5) = 24 - (-8) = 24 + 8 = 32.

Final Answer:

(h2f)(5)=32.(h - 2f)(5) = 32.


Would you like a breakdown of any step? Let me know!


Here are 5 related questions for further practice:

  1. If g(x)=2x3g(x) = 2x - 3, what is (h+g)(2)(h + g)(2)?
  2. Evaluate (hf)(3)(h \cdot f)(3) for the same functions h(x)h(x) and f(x)f(x).
  3. Find (fh)(x)(f - h)(x) in terms of xx (as a new function).
  4. Solve for xx if h(x)=f(x)h(x) = f(x).
  5. Calculate (2h+3f)(4)(2h + 3f)(4).

Tip: Always simplify expressions before substituting values—it saves time and reduces errors!

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Math Problem Analysis

Mathematical Concepts

Function evaluation
Algebra
Substitution

Formulas

(h - 2f)(x) = h(x) - 2f(x)
h(x) = x^2 - 1
f(x) = -x + 1

Theorems

-

Suitable Grade Level

Grade 8-10