Consider the lines
y = 3x + 5
2y = 4x + 5
3y = x - 2
2y = 3x - 2
4y = x - 5
Let's say that a pair of lines is good if the two lines are either parallel or perpendicular to each other. Among all the pairs of lines shown, how many pairs are good?
+14905 How many pairs are good?
Hello Guest!
a y = 3x + 5 m = 3
b 2y = 4x + 5 m = 2
c 3y = x - 2 m = 1/3
d 2y = 3x - 2 m = 3/2
e 4y = x - 5 m = 1/4
No pairs are good.
!
+14905 Hello Guest #2!
I have isolated y in all lines: I divide the line by the y-coefficient.
The x-coefficient is the slope of the line.
If two lines have the same slopes,
they are a good pair. Parallel course.
If two lines have the same, slope and negative reciprocal of the slope,
then they are a good pair. Perpendicular course
!
