5x-4y=-9 What is the slope of a line perpendicular tothis line? What is theslope of a line parallel to this li

Answer 1

First, get the equation of the line into the slope-intercept form y = mx + b (i.e., express y):

5x-4y=-9
4y = 5x + 9
y = 5/4 x + 9/4

---> the slope of this line is 5/4 (and the y-intercept is 9/4)

---> any line parallel to this one will have the same slope!
=> slope of a parallel line: m = 5/4

---> The slopes m and n of two perpendicular lines satisfy the condition: m·n = -1
=> any line perpendicular to this line will have slope
m = -1 / (5/4) = -4/5

Hope this helps.

Answer 2

5x - 4y = -9

y = (-5x - 9) / -4

y = -5/-4 x - 9/-4

y = 5/4 x + 9/4

slope is 5/4 (all lines parallel)

Perpendicular lines are the negative reciprocal of the slope, which is -4/5 .

Answer 3

First, what is the slope of this line? Solve it for y.

4y = 5x + 9
or
y = 5/4 x + 9/4

So, this line and any line parallel to it will have a slope of 5/4.

Now, any line perp. to this line will have a slope that is -1 over this slope, also the negative recipricol or -4/5.

Answer 4

4y = 5x + 9
y = (5/4).x + 9/4

Perpendicular line has slope (- 4 / 5)
Parallel line has slope 5 / 4