MHB Slope Intercept Equation with parallel

  • Thread starter Thread starter mhester88
  • Start date Start date
  • Tags Tags
    Parallel Slope
Click For Summary
To find the slope-intercept equation of a line parallel to -9x - 7y = 4 with the same y-intercept as -5x + 11y = -22, first convert both equations to slope-intercept form. The first equation simplifies to y = (-9/7)x - 4/7, indicating a slope of -9/7. The y-intercept from the second equation is found to be -2. Therefore, the parallel line can be expressed as y = (-9/7)x - 2, or in a more simplified form, 9x + 7y = -14. This process illustrates how to derive parallel lines with shared y-intercepts in slope-intercept form.
mhester88
Messages
3
Reaction score
0
I'm not understanding this question at all and am not sure how to even begin answering this. Any help would be appreciated.

Write the slope-intercept equation of the line that is parallel to -9x-7y=4 and has the same y-intercept as the graph of -5x+11y=-22.
 
Mathematics news on Phys.org
start by converting both of the given equations to slope-intercept form (y = mx + b, correct?)

parallel lines have the same slope
 
mhester88 said:
I'm not understanding this question at all and am not sure how to even begin answering this. Any help would be appreciated.

Write the slope-intercept equation of the line that is parallel to -9x-7y=4 and has the same y-intercept as the graph of -5x+11y=-22.
Since this was posted 6 months ago:
-9x- 7y= 4 is the same as 7y= -9x- 4 or y= (-9/7)x- 4/7. That has slope -9/7. Any line parallel to it has the same slope so can be written y= (-9/7)x+ c for some number c.

The y-intercept of a graph is the point (0, y) where the graph crosses the y-axis. Setting x= 0 in -5x+ 11y= -22, 11y= -22 so y= -2. The y-intercept is (0, -2). Setting x= 0 in y= (-9/7)x+ c, y= c and we want that to be -2.

y= (-9/7)x- 2. If, like me, you don't like fractions, multiply both sides by 7:
7y= -9x- 14.

You could also add 9x to both sides to get the slightly "prettier"
9x+ 7y= -14.