Math Problem Statement

Multiple math problems involving function evaluation and quadratic motion.

Solution

Let's go through each question in the image step by step.


1. What is f(1)f(-1) if f(x)=x3x2+2x7f(x) = -x^3 - x^2 + 2x - 7?

To find f(1)f(-1), substitute x=1x = -1 into the function:

f(1)=(1)3(1)2+2(1)7f(-1) = -(-1)^3 - (-1)^2 + 2(-1) - 7 f(1)=1127=9f(-1) = 1 - 1 - 2 - 7 = -9

Answer: B. f(1)=9f(-1) = -9


2. Evaluate the given function if x=a1x = a - 1, f(x)=2x29f(x) = 2x^2 - 9?

Substitute x=a1x = a - 1 into the function:

f(a1)=2(a1)29f(a-1) = 2(a-1)^2 - 9 f(a1)=2(a22a+1)9f(a-1) = 2(a^2 - 2a + 1) - 9 f(a1)=2a24a+29=2a24a7f(a-1) = 2a^2 - 4a + 2 - 9 = 2a^2 - 4a - 7

Answer: A. f(a1)=2a24a7f(a-1) = 2a^2 - 4a - 7


3. What is k(b)k(-b) if k(x)=2x2x9k(x) = 2x^2 - x - 9?

Substitute x=bx = -b into the function:

k(b)=2(b)2(b)9k(-b) = 2(-b)^2 - (-b) - 9 k(b)=2b2+b9k(-b) = 2b^2 + b - 9

Answer: D. 2b2+b92b^2 + b - 9


4. A projectile is shot upward from 5m above the ground with an initial velocity of 35 m/s. The height of the projectile, ss, in meters after tt seconds is given by s(t)=5+35t9.8t2s(t) = 5 + 35t - 9.8t^2. Calculate the height after 2.5 seconds.

Substitute t=2.5t = 2.5 into the equation:

s(2.5)=5+35(2.5)9.8(2.5)2s(2.5) = 5 + 35(2.5) - 9.8(2.5)^2 s(2.5)=5+87.59.8(6.25)s(2.5) = 5 + 87.5 - 9.8(6.25) s(2.5)=5+87.561.25=31.25meterss(2.5) = 5 + 87.5 - 61.25 = 31.25 \, \text{meters}

Answer: B. 31.25 meters


5. What is f(1)f(1) if f(x)=x3x2+2x7f(x) = -x^3 - x^2 + 2x - 7?

Substitute x=1x = 1 into the function:

f(1)=(1)3(1)2+2(1)7f(1) = -(1)^3 - (1)^2 + 2(1) - 7 f(1)=11+27=7f(1) = -1 - 1 + 2 - 7 = -7

Answer: B. f(1)=7f(1) = -7


Would you like further explanations or have any questions?

Here are five related questions to deepen understanding:

  1. How do you evaluate polynomial functions for any given value of xx?
  2. What happens to the value of a function if xx is negative or positive?
  3. How does the quadratic term x2x^2 affect the shape of a function's graph?
  4. How can you find the maximum height of a projectile in a quadratic motion problem?
  5. How would you solve the same type of function evaluation problems using a graphing approach?

Tip: Always substitute values carefully when evaluating functions, and pay special attention to signs when squaring or dealing with negative terms.

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Math Problem Analysis

Mathematical Concepts

Function Evaluation
Quadratic Functions
Projectile Motion

Formulas

f(x) = -x^3 - x^2 + 2x - 7
f(x) = 2x^2 - 9
k(x) = 2x^2 - x - 9
s(t) = 5 + 35t - 9.8t^2

Theorems

Polynomial Function Evaluation
Quadratic Formula
Equations of Motion

Suitable Grade Level

Grades 9-12