Math Problem Statement

1) Given that f(x) is a linear function where f(2) = 9 and f(-2) = -11, determine: (i) f(x), (ii) f(0.2). 2) Given that f(x) is a linear function where f(2) + f(3) = 0 and f(5) = 5, determine: (i) f(x), (ii) f(-2).

Solution

Let's solve these problems step by step.


1) Given that f(x)f(x) is a linear function where f(2)=9f(2) = 9 and f(2)=11f(-2) = -11, determine:

(i) f(x)f(x)

Since f(x)f(x) is linear, it can be written as: f(x)=mx+cf(x) = mx + c where mm is the slope and cc is the y-intercept.

  1. Find the slope (mm): Using the formula for slope between two points: m=f(2)f(2)2(2)=9(11)4=204=5m = \frac{f(2) - f(-2)}{2 - (-2)} = \frac{9 - (-11)}{4} = \frac{20}{4} = 5

  2. Substitute m=5m = 5 into f(x)=mx+cf(x) = mx + c: f(x)=5x+cf(x) = 5x + c

  3. Find cc using one of the points, say (2,9)(2, 9): Substitute x=2x = 2 and f(x)=9f(x) = 9: 9=5(2)+c    9=10+c    c=19 = 5(2) + c \implies 9 = 10 + c \implies c = -1

  4. Final equation: f(x)=5x1f(x) = 5x - 1

(ii) f(0.2)f(0.2)

Substitute x=0.2x = 0.2 into f(x)=5x1f(x) = 5x - 1: f(0.2)=5(0.2)1=11=0f(0.2) = 5(0.2) - 1 = 1 - 1 = 0


2) Given that f(x)f(x) is a linear function where f(2)+f(3)=0f(2) + f(3) = 0 and f(5)=5f(5) = 5, determine:

(i) f(x)f(x)

  1. Express f(x)f(x): Again, let: f(x)=mx+cf(x) = mx + c

  2. Use the condition f(2)+f(3)=0f(2) + f(3) = 0: Substitute f(2)=2m+cf(2) = 2m + c and f(3)=3m+cf(3) = 3m + c: (2m+c)+(3m+c)=0    5m+2c=0    2c=5m    c=5m2(2m + c) + (3m + c) = 0 \implies 5m + 2c = 0 \implies 2c = -5m \implies c = -\frac{5m}{2}

  3. **Use the condition ( f(5) =

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Math Problem Analysis

Mathematical Concepts

Linear Functions
Algebra

Formulas

Slope formula m = (y2 - y1) / (x2 - x1)
Linear equation f(x) = mx + c

Theorems

Basic properties of linear functions

Suitable Grade Level

Grades 8-10