Math Problem Statement

write the equation of a line that passes through (3,7) and is perpendicular to 2x+4y=8

Solution

To find the equation of the line that passes through (3,7)(3, 7) and is perpendicular to the given line 2x+4y=82x + 4y = 8, follow these steps:

Step 1: Find the slope of the given line

First, rearrange the given equation 2x+4y=82x + 4y = 8 into slope-intercept form y=mx+by = mx + b, where mm is the slope.

2x+4y=82x + 4y = 8 4y=2x+84y = -2x + 8 y=12x+2y = -\frac{1}{2}x + 2

So, the slope m1m_1 of the given line is 12-\frac{1}{2}.

Step 2: Find the slope of the perpendicular line

The slopes of two perpendicular lines are negative reciprocals of each other. The slope of the line we're looking for will be the negative reciprocal of 12-\frac{1}{2}.

m2=1(12)=2m_2 = -\frac{1}{\left(-\frac{1}{2}\right)} = 2

Step 3: Use point-slope form to write the equation

Now that we know the slope of the perpendicular line is 22 and it passes through the point (3,7)(3, 7), use the point-slope form of a line equation:

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

Substitute m=2m = 2, x1=3x_1 = 3, and y1=7y_1 = 7:

y7=2(x3)y - 7 = 2(x - 3)

Step 4: Simplify the equation

Expand and simplify the equation:

y7=2x6y - 7 = 2x - 6 y=2x+1y = 2x + 1

Thus, the equation of the line that passes through (3,7)(3, 7) and is perpendicular to 2x+4y=82x + 4y = 8 is:

y=2x+1y = 2x + 1

Would you like any further clarification or details?


Here are five related questions to deepen your understanding:

  1. What would the equation of the line be if it were parallel to 2x+4y=82x + 4y = 8?
  2. How do you find the distance between two parallel lines?
  3. Can you generalize how to find perpendicular slopes for any linear equation?
  4. How does the point-slope form compare to the slope-intercept form for different types of problems?
  5. What is the significance of negative reciprocals in perpendicular lines?

Tip: Always simplify the given equation into slope-intercept form first to easily identify the slope when solving line-related problems.

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Math Problem Analysis

Mathematical Concepts

Algebra
Linear Equations
Slopes of Perpendicular Lines

Formulas

Slope-intercept form: y = mx + b
Point-slope form: y - y1 = m(x - x1)
Negative reciprocal for perpendicular slopes

Theorems

Perpendicular slopes theorem

Suitable Grade Level

Grades 9-10