Math Problem Statement

If f(x) is a linear function, f(-3) = 4, and f(2) = -4, find an equation for f(x).

Solution

To solve the problem, we need to find the equation of the linear function f(x)f(x) given the points (3,4)(-3, 4) and (2,4)(2, -4).

Step 1: General form of a linear function

The equation of a linear function is given by: f(x)=mx+bf(x) = mx + b where mm is the slope and bb is the y-intercept.

Step 2: Calculate the slope (mm)

The slope mm between two points (x1,y1)(x_1, y_1) and (x2,y2)(x_2, y_2) is: m=y2y1x2x1m = \frac{y_2 - y_1}{x_2 - x_1}

Substituting (x1,y1)=(3,4)(x_1, y_1) = (-3, 4) and (x2,y2)=(2,4)(x_2, y_2) = (2, -4): m=442(3)=85m = \frac{-4 - 4}{2 - (-3)} = \frac{-8}{5} Thus, m=85m = -\frac{8}{5}.

Step 3: Substitute into the linear equation

The equation now is: f(x)=85x+bf(x) = -\frac{8}{5}x + b

Step 4: Solve for bb

We substitute one of the given points into the equation to find bb. Using (3,4)(-3, 4): 4=85(3)+b4 = -\frac{8}{5}(-3) + b Simplify: 4=245+b4 = \frac{24}{5} + b Subtract 245\frac{24}{5} from both sides: b=4245=205245=45b = 4 - \frac{24}{5} = \frac{20}{5} - \frac{24}{5} = -\frac{4}{5}

Step 5: Final equation

The equation for f(x)f(x) is: f(x)=85x45f(x) = -\frac{8}{5}x - \frac{4}{5}

Let me know if you want additional clarifications or have further questions!


Related Questions:

  1. What is the slope-intercept form of a linear equation and how does it relate to this problem?
  2. How can you verify that this equation satisfies both given points?
  3. How would the equation change if f(x)f(x) were quadratic instead of linear?
  4. Can you rewrite the equation in standard form Ax+By=CAx + By = C?
  5. How do changes in the slope affect the steepness of a line?

Tip: Always verify your equation by plugging in the given points to ensure the result is correct.

Ask a new question for Free

By Image

Drop file here or Click Here to upload

Math Problem Analysis

Mathematical Concepts

Linear Functions
Slope-Intercept Form
Algebra

Formulas

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

Theorems

Linear equation properties
Two-point form of a line

Suitable Grade Level

Grades 8-10