Math Problem Statement

If f(x) is a linear function, f(-2)=-3, and f(4)=-5, find an equation for f(x)

f(x) =  

Solution

To find the equation for the linear function f(x)f(x), we need to determine the slope mm and the y-intercept bb of the line. The general form of a linear equation is:

f(x)=mx+bf(x) = mx + b

Step 1: Find the slope mm

The slope mm is calculated as the change in f(x)f(x) over the change in xx. We are given two points: (2,3)and(4,5)(-2, -3) \quad \text{and} \quad (4, -5) Using the slope formula: m=f(4)f(2)4(2)=5(3)4(2)=5+34+2=26=13m = \frac{f(4) - f(-2)}{4 - (-2)} = \frac{-5 - (-3)}{4 - (-2)} = \frac{-5 + 3}{4 + 2} = \frac{-2}{6} = -\frac{1}{3}

Step 2: Find the y-intercept bb

Now that we know m=13m = -\frac{1}{3}, we can use one of the given points to solve for bb. Let's use the point (2,3)(-2, -3).

Substitute x=2x = -2, f(x)=3f(x) = -3, and m=13m = -\frac{1}{3} into the equation: 3=13(2)+b-3 = -\frac{1}{3}(-2) + b Simplify: 3=23+b-3 = \frac{2}{3} + b Subtract 23\frac{2}{3} from both sides: b=323=9323=113b = -3 - \frac{2}{3} = \frac{-9}{3} - \frac{2}{3} = \frac{-11}{3}

Step 3: Write the equation

Now that we know m=13m = -\frac{1}{3} and b=113b = \frac{-11}{3}, the equation for f(x)f(x) is: f(x)=13x113f(x) = -\frac{1}{3}x - \frac{11}{3}

Would you like more details or have any questions?

Here are 5 related questions:

  1. How do you verify the correctness of the linear equation using given points?
  2. What are the steps for finding the slope between two points?
  3. How do you graph a linear function given the equation?
  4. How would the equation change if the slope were positive?
  5. What is the significance of the y-intercept in a linear equation?

Tip: Always double-check your slope calculation by ensuring you subtract the values of f(x)f(x) and xx in the correct order!

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Math Problem Analysis

Mathematical Concepts

Algebra
Linear Functions
Slopes

Formulas

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

Theorems

Linear Equation Properties

Suitable Grade Level

Grades 8-10