Line [tex]$k$[/tex] has the equation [tex]$y = \frac{3}{4}x + 42$[/tex].

a. Write an equation of the line parallel to line [tex]$k$[/tex] that passes through the point [tex]$(24, -15)$[/tex].

b. Write an equation of the line perpendicular to line [tex]$k$[/tex] that passes through the point [tex]$(24, -15)$[/tex].



Answer :

To solve this problem, we need to write the equations of lines that are parallel and perpendicular to the given line [tex]\( k \)[/tex], which passes through the point [tex]\( (24, -15) \)[/tex].

Step-by-Step Solution:

### Part (a): Equation of the Parallel Line

A line that is parallel to another line has the same slope.

1. Identify the slope of the given line [tex]\( k \)[/tex]:
The equation of line [tex]\( k \)[/tex] is [tex]\( y = \frac{3}{4} x + 42 \)[/tex]. The slope (m) of this line is [tex]\( \frac{3}{4} \)[/tex].

2. Use the Point-Slope Form to find the equation of the parallel line:
The point-slope form for the equation of a line is:
[tex]\[ y - y_1 = m(x - x_1) \][/tex]
Here, [tex]\( m = \frac{3}{4} \)[/tex], [tex]\( x_1 = 24 \)[/tex], and [tex]\( y_1 = -15 \)[/tex].

3. Substitute the values into the point-slope form:
[tex]\[ y - (-15) = \frac{3}{4} (x - 24) \][/tex]
Simplifying this:
[tex]\[ y + 15 = \frac{3}{4}x - \frac{3}{4} \cdot 24 \][/tex]
[tex]\[ y + 15 = \frac{3}{4}x - 18 \][/tex]

4. Rewrite it into slope-intercept form [tex]\( y = mx + b \)[/tex]:
[tex]\[ y = \frac{3}{4} x - 18 - 15 \][/tex]
[tex]\[ y = \frac{3}{4} x - 33 \][/tex]

So the equation of the line parallel to line [tex]\( k \)[/tex] that passes through [tex]\( (24, -15) \)[/tex] is:
[tex]\[ y = \frac{3}{4} x - 33 \][/tex]

### Part (b): Equation of the Perpendicular Line

A line that is perpendicular to another line has a slope that is the negative reciprocal of the original line's slope.

1. Identify the slope of the given line [tex]\( k \)[/tex]:
The slope of line [tex]\( k \)[/tex] is [tex]\( \frac{3}{4} \)[/tex].

2. Find the negative reciprocal of the slope:
The negative reciprocal of [tex]\( \frac{3}{4} \)[/tex] is [tex]\( -\frac{4}{3} \)[/tex].

3. Use the Point-Slope Form to find the equation of the perpendicular line:
Again, use the point-slope form with:
[tex]\[ y - y_1 = m(x - x_1) \][/tex]
Here, [tex]\( m = -\frac{4}{3} \)[/tex], [tex]\( x_1 = 24 \)[/tex], and [tex]\( y_1 = -15 \)[/tex].

4. Substitute the values into the point-slope form:
[tex]\[ y - (-15) = -\frac{4}{3} (x - 24) \][/tex]
Simplifying this:
[tex]\[ y + 15 = -\frac{4}{3}x + \frac{4}{3} \cdot 24 \][/tex]
[tex]\[ y + 15 = -\frac{4}{3}x + 32 \][/tex]

5. Rewrite it into slope-intercept form [tex]\( y = mx + b \)[/tex]:
[tex]\[ y = -\frac{4}{3} x + 32 - 15 \][/tex]
[tex]\[ y = -\frac{4}{3} x + 17 \][/tex]

So the equation of the line perpendicular to line [tex]\( k \)[/tex] that passes through [tex]\( (24, -15) \)[/tex] is:
[tex]\[ y = -\frac{4}{3} x + 17 \][/tex]

Therefore, the final results are:
- The parallel line equation: [tex]\( y = \frac{3}{4} x - 33 \)[/tex]
- The perpendicular line equation: [tex]\( y = -\frac{4}{3} x + 17 \)[/tex]