Math Problem Statement

A line passes through the points 

(

2

,

2

)

 and 

(

3

,

9

)

.

 Write its equation in slope-intercept form.

Solution

To find the equation of the line in slope-intercept form (y=mx+by = mx + b), we need the slope (mm) and the yy-intercept (bb).

Step 1: Calculate the slope (mm)

The formula for the slope is: m=y2y1x2x1m = \frac{y_2 - y_1}{x_2 - x_1} Substitute the given points (2,2)(2, -2) and (3,9)(3, -9): m=9(2)32=9+21=71=7m = \frac{-9 - (-2)}{3 - 2} = \frac{-9 + 2}{1} = \frac{-7}{1} = -7

Step 2: Use the point-slope formula to find the equation

The point-slope form is: yy1=m(xx1)y - y_1 = m(x - x_1) Substitute m=7m = -7 and one of the points, say (2,2)(2, -2): y(2)=7(x2)y - (-2) = -7(x - 2) Simplify: y+2=7x+14y + 2 = -7x + 14 y=7x+12y = -7x + 12

Final Answer:

The equation of the line in slope-intercept form is: y=7x+12y = -7x + 12


Would you like a detailed explanation of any step?

Here are 5 related questions for further exploration:

  1. How do you find the equation of a line if only the slope and one point are given?
  2. How can you verify if a point lies on a given line?
  3. What is the slope-intercept form of a vertical line?
  4. What happens to the slope when two points have the same yy-coordinate?
  5. How do you convert slope-intercept form to standard form?

Tip: When working with slopes, always subtract coordinates in the same order to avoid sign errors!

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Math Problem Analysis

Mathematical Concepts

Linear Equations
Slope-Intercept Form
Point-Slope Form

Formulas

Slope formula: m = (y2 - y1) / (x2 - x1)
Point-slope form: y - y1 = m(x - x1)
Slope-intercept form: y = mx + b

Theorems

Line equation theorem: A straight line in a plane can be expressed as y = mx + b when slope and intercept are known.

Suitable Grade Level

Grades 8-10