Math Problem Statement

Write an equation of the line that passes through the given points. (-4,7) and (2,-1)

Solution

To find the equation of the line that passes through the points (4,7)(-4, 7) and (2,1)(2, -1), we can use the point-slope formula and calculate the slope first:

Step 1: Calculate the slope (mm)

The slope formula is:

m=y2y1x2x1m = \frac{y_2 - y_1}{x_2 - x_1}

Substituting the given points: m=172(4)=86=43m = \frac{-1 - 7}{2 - (-4)} = \frac{-8}{6} = -\frac{4}{3}

Step 2: Use the point-slope form of the equation

The point-slope formula is:

yy1=m(xx1)y - y_1 = m(x - x_1)

We can use either of the points, say (4,7)(-4, 7): y7=43(x(4))y - 7 = -\frac{4}{3}(x - (-4))

Simplify: y7=43(x+4)y - 7 = -\frac{4}{3}(x + 4)

Step 3: Simplify to slope-intercept form (y=mx+by = mx + b)

Distribute the slope: y7=43x163y - 7 = -\frac{4}{3}x - \frac{16}{3}

Add 7 to both sides (convert 77 to 213\frac{21}{3}): y=43x163+213y = -\frac{4}{3}x - \frac{16}{3} + \frac{21}{3}

Simplify: y=43x+53y = -\frac{4}{3}x + \frac{5}{3}

Final Answer:

The equation of the line is: y=43x+53y = -\frac{4}{3}x + \frac{5}{3}


Do you want a breakdown of how to check this solution? Here are 5 related questions to consider:

  1. How do you verify if both points satisfy the equation of the line?
  2. Can you rewrite the equation in standard form Ax+By=CAx + By = C?
  3. What is the importance of slope in identifying the steepness of a line?
  4. How does the midpoint between (4,7)(-4, 7) and (2,1)(2, -1) relate to this line?
  5. How would the equation change if the slope were positive instead?

Tip: Always double-check slope calculations carefully to avoid sign errors when subtracting.

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Math Problem Analysis

Mathematical Concepts

Algebra
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

Concept of slope
Linear equation transformations

Suitable Grade Level

Grades 8-10