Math Problem Statement

Find a formula for each function graphed below, referring to part a and part b of the image.

Solution

The question asks to find a formula for each function graphed in parts a and b of the figure.

Part a:

The points given are approximately:

  • (-1, 4)
  • (2, 1)

These suggest a linear relationship. The formula for a linear equation is y=mx+by = mx + b, where mm is the slope, and bb is the y-intercept.

To find the slope mm, we use: m=y2y1x2x1=142(1)=33=1m = \frac{y_2 - y_1}{x_2 - x_1} = \frac{1 - 4}{2 - (-1)} = \frac{-3}{3} = -1

Now, using the point-slope form of the equation, we can plug in one of the points (for example, (2,1)(2, 1)) to find the y-intercept bb: y=12+b=1    b=3y = -1 \cdot 2 + b = 1 \implies b = 3

Thus, the equation of the line is: y=x+3y = -x + 3

Part b:

The points given are approximately:

  • (-3, -1)
  • (1, -3)
  • (3, 3)

This looks like a piecewise function:

  1. From (3,1)(-3, -1) to (1,3)(1, -3), calculate the slope: m1=3(1)1(3)=24=12m_1 = \frac{-3 - (-1)}{1 - (-3)} = \frac{-2}{4} = -\frac{1}{2} Using the point (3,1)(-3, -1) to find the equation for this segment: y=12(x+3)1y = -\frac{1}{2}(x + 3) - 1 This simplifies to: y=12x52y = -\frac{1}{2}x - \frac{5}{2}

  2. From (1,3)(1, -3) to (3,3)(3, 3), calculate the slope: m2=3(3)31=62=3m_2 = \frac{3 - (-3)}{3 - 1} = \frac{6}{2} = 3 Using the point (1,3)(1, -3): y=3(x1)3y = 3(x - 1) - 3 This simplifies to: y=3x6y = 3x - 6

Thus, the piecewise function is:

-\frac{1}{2}x - \frac{5}{2}, & \text{for } -3 \leq x \leq 1 \\ 3x - 6, & \text{for } 1 \leq x \leq 3 \end{cases}$$ Do you need further explanation on any part of this solution? Here are 5 follow-up questions you might find useful: 1. How do you find the slope between two points? 2. What is the point-slope form of a line, and how is it used? 3. What is a piecewise function, and how do you identify it from a graph? 4. How do you solve for the y-intercept of a line when given a point and the slope? 5. How do you write an equation for a line segment in a piecewise function? **Tip**: When working with piecewise functions, carefully examine the changes in slope at each segment to identify breaks in the graph!

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Math Problem Analysis

Mathematical Concepts

Linear Equations
Piecewise Functions
Slope-Intercept Form

Formulas

y = mx + b (Slope-Intercept Form)
Point-Slope Formula: y - y1 = m(x - x1)

Theorems

Slope Formula
Point-Slope Form
Piecewise Functions Definition

Suitable Grade Level

Grades 9-12