Math Problem Statement

A line passes through the point (9,-2) and has a slope of -4/3. Write an equation in slope-intercept form for this line. please explain each step.

Solution

To find the equation of a line in slope-intercept form (y=mx+by = mx + b), we follow these steps:


Step 1: Recall the slope-intercept form of the line

The general form is: y=mx+by = mx + b Where:

  • mm is the slope of the line.
  • bb is the y-intercept, which is the value of yy when x=0x = 0.

Here, the slope m=43m = -\frac{4}{3} is given, and the line passes through the point (9,2)(9, -2).


Step 2: Substitute the slope and the point into the line equation

At the point (9,2)(9, -2), the coordinates x=9x = 9 and y=2y = -2. Plug these values into the equation y=mx+by = mx + b: 2=43(9)+b-2 = -\frac{4}{3}(9) + b


Step 3: Solve for bb (the y-intercept)

Simplify 43(9)-\frac{4}{3}(9): 43(9)=12-\frac{4}{3}(9) = -12 Thus: 2=12+b-2 = -12 + b Add 1212 to both sides to solve for bb: b=2+12b = -2 + 12 b=10b = 10


Step 4: Write the final equation

Now that we know m=43m = -\frac{4}{3} and b=10b = 10, substitute these into the slope-intercept form: y=43x+10y = -\frac{4}{3}x + 10


Final Answer:

The equation of the line in slope-intercept form is: y=43x+10y = -\frac{4}{3}x + 10


Would you like me to graph this line or verify it with additional calculations? 😊

5 Related Questions:

  1. How do you convert a slope-intercept form equation into standard form?
  2. What is the significance of the slope value in the line equation?
  3. How do you find the equation of a line if two points are given instead of one?
  4. How does the y-intercept change the position of the line on the graph?
  5. What happens to the line if the slope is positive instead of negative?

Tip:

Always double-check calculations when solving for bb to avoid arithmetic errors!

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Math Problem Analysis

Mathematical Concepts

Algebra
Linear Equations
Slope-Intercept Form

Formulas

y = mx + b (slope-intercept form)

Theorems

Point-Slope Relationship in Linear Equations

Suitable Grade Level

Grades 8-10