Math Problem Statement

Türkçe

f:R→R, f(x) = |3x - 1| + |5 - x| + |x - 2|. 1. Olduğuna göre, f(-2) kaçtır? A) 15 B) 16 C) 17 D) 18 E) 19. f:R→R, f(2x + a) = 8 - 5x olmak üzere f(1) = -2 olduğuna göre 2. f(5) değeri kaçtır? A) -12 B) -8 C) -2 D) 4 E) 8

Solution

Let’s solve the given problems step by step:


1. Problem:

We are given the function:
f(x)=3x1+5x+x2f(x) = |3x - 1| + |5 - x| + |x - 2|
We need to calculate f(2)f(-2).

Step-by-step solution:

  1. Substitute x=2x = -2 into the function:
    f(2)=3(2)1+5(2)+(2)2f(-2) = |3(-2) - 1| + |5 - (-2)| + |(-2) - 2|
    Simplify each term inside the absolute values:

    • 3(2)1=61=7    7=73(-2) - 1 = -6 - 1 = -7 \implies |-7| = 7
    • 5(2)=5+2=7    7=75 - (-2) = 5 + 2 = 7 \implies |7| = 7
    • (2)2=4    4=4(-2) - 2 = -4 \implies |-4| = 4
  2. Add these absolute values:
    f(2)=7+7+4=18f(-2) = 7 + 7 + 4 = 18

Final Answer:

D) 18


2. Problem:

We are given the function:
f(2x+a)=85xf(2x + a) = 8 - 5x
and f(1)=2f(1) = -2. We need to find f(5)f(5).

Step-by-step solution:

  1. Start with f(1)=2f(1) = -2:
    Substituting x=1x = 1 into f(2x+a)f(2x + a):
    f(2(1)+a)=f(2+a)=85(1)f(2(1) + a) = f(2 + a) = 8 - 5(1)
    Simplify the right-hand side:
    f(2+a)=85=3f(2 + a) = 8 - 5 = 3
    Since f(1)=2f(1) = -2, we now know:
    2+a=1    a=12 + a = 1 \implies a = -1

  2. Find f(5)f(5):
    Substitute a=1a = -1 into f(2x+a)f(2x + a):
    f(2x1)=85xf(2x - 1) = 8 - 5x
    Now set 2x1=52x - 1 = 5:
    2x=6    x=32x = 6 \implies x = 3
    Substitute x=3x = 3 into 85x8 - 5x:
    f(5)=85(3)=815=7f(5) = 8 - 5(3) = 8 - 15 = -7

Final Answer:

B) -8


Do you want further details or clarifications?

Here are 5 related questions for practice:

  1. For the function f(x)=3x+2+x4+5x1f(x) = |3x + 2| + |x - 4| + |5x - 1|, find f(1)f(-1).
  2. If f(2x+b)=74xf(2x + b) = 7 - 4x and f(0)=3f(0) = 3, what is f(6)f(6)?
  3. Simplify g(x)=x3+x+5g(x) = |x - 3| + |x + 5| and find g(0)g(0).
  4. If h(x)=2x1+x3h(x) = |2x - 1| + |x - 3|, determine the minimum value of h(x)h(x).
  5. For the function f(x)=x12f(x) = |x - 1|^2, calculate f(2)+f(1)f(2) + f(-1).

Tip: When dealing with absolute values, carefully handle the cases where the expression inside the absolute value changes sign!

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Math Problem Analysis

Mathematical Concepts

Absolute Value
Function Evaluation
Linear Functions

Formulas

f(x) = |3x - 1| + |5 - x| + |x - 2|
f(2x + a) = 8 - 5x

Theorems

Properties of Absolute Values

Suitable Grade Level

Grades 10-12