Math Problem Statement

The equation for line j can be written as y = 1/2x - 4. Parallel to line j is line k, which passes through the point (-8, -5). What is the equation of line k?

Solution

We are tasked with finding the equation of line kk, which is parallel to line jj. The equation for line jj is given as:

y=12x4y = \frac{1}{2}x - 4

Step 1: Identify the slope of line jj

The slope-intercept form of a line is:

y=mx+by = mx + b

where mm is the slope. From the equation y=12x4y = \frac{1}{2}x - 4, we see that the slope mm is 12\frac{1}{2}.

Step 2: Use the same slope for line kk

Since line kk is parallel to line jj, they share the same slope. Therefore, the slope of line kk is also 12\frac{1}{2}.

Step 3: Use the point-slope form

We are given that line kk passes through the point (8,5)(-8, -5). To find the equation of line kk, we use the point-slope form of a line:

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

where mm is the slope and (x1,y1)(x_1, y_1) is the point the line passes through. Substituting the values:

  • m=12m = \frac{1}{2}
  • x1=8x_1 = -8
  • y1=5y_1 = -5

we get:

y(5)=12(x(8))y - (-5) = \frac{1}{2}(x - (-8))

This simplifies to:

y+5=12(x+8)y + 5 = \frac{1}{2}(x + 8)

Step 4: Solve for yy

Now we solve for yy to put the equation into slope-intercept form:

y+5=12x+12(8)y + 5 = \frac{1}{2}x + \frac{1}{2}(8) y+5=12x+4y + 5 = \frac{1}{2}x + 4 y=12x+45y = \frac{1}{2}x + 4 - 5 y=12x1y = \frac{1}{2}x - 1

Final Answer:

The equation of line kk is:

y=12x1y = \frac{1}{2}x - 1

Would you like more details on any of the steps?

Here are some additional questions related to this problem:

  1. How do you find the slope of a line given two points on the line?
  2. What is the difference between parallel and perpendicular lines in terms of their slopes?
  3. How can you convert the equation of a line from point-slope form to slope-intercept form?
  4. What would the equation of line kk be if it were perpendicular to line jj instead?
  5. How do you check if a given point lies on a line?

Tip: When two lines are parallel, their slopes are always equal!

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Math Problem Analysis

Mathematical Concepts

Algebra
Linear Equations
Point-Slope Form
Slope-Intercept Form

Formulas

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

Theorems

Parallel lines have the same slope.

Suitable Grade Level

Grades 8-10