Questions: The equation for line j can be written as y=-5/7 x-10. Line k, which is parallel to line j, includes the point (-9,5). What is the equation of line k?
Write the equation in slope-intercept form. Write the numbers in the equation as simplified proper fractions, improper fractions, or integers.
Transcript text: The equation for line $j$ can be written as $y=-\frac{5}{7} x-10$. Line $k$, which is parallel to line $j$, includes the point $(-9,5)$. What is the equation of line $k$ ?
Write the equation in slope-intercept form. Write the numbers in the equation as simplified proper fractions, improper fractions, or integers.
Solution
Solution Steps
To find the equation of a line parallel to a given line, we need to use the same slope as the given line. The given line's equation is \( y = -\frac{5}{7}x - 10 \), so the slope is \( -\frac{5}{7} \). We then use the point-slope form of the equation of a line, \( y - y_1 = m(x - x_1) \), where \( m \) is the slope and \( (x_1, y_1) \) is the given point. Finally, we convert the equation to slope-intercept form, \( y = mx + b \).
Step 1: Identify the Slope
The slope of the given line \( j \) is \( m = -\frac{5}{7} \). Since line \( k \) is parallel to line \( j \), it will have the same slope.
Step 2: Use the Point-Slope Form
Using the point-slope form of the equation of a line, we have:
\[
y - y_1 = m(x - x_1)
\]
Substituting \( m = -\frac{5}{7} \) and the point \( (-9, 5) \):
\[
y - 5 = -\frac{5}{7}(x + 9)
\]
Step 3: Convert to Slope-Intercept Form
Expanding and rearranging the equation:
\[
y - 5 = -\frac{5}{7}x - \frac{45}{7}
\]
Adding 5 (which is \( \frac{35}{7} \)) to both sides:
\[
y = -\frac{5}{7}x - \frac{45}{7} + \frac{35}{7}
\]
This simplifies to:
\[
y = -\frac{5}{7}x - \frac{10}{7}
\]
Final Answer
The equation of line \( k \) in slope-intercept form is
\[
\boxed{y = -\frac{5}{7}x - \frac{10}{7}}
\]