Question

Find the slope of a line perpendicular to the graph of each equation

y=2x

y=-3x

y= 7/5x-2

Answer 1

If a line has a slope of m, the perpendicular line has a slope of -1/m.

Answer 2

Does that help?

Answer 3

not really

Answer 4

Do you know how to find the slope of a line?

Answer 5

yes
by using y=mx+b

Answer 6

ok so if y=2x, what's the slope?

Answer 7

2?

Answer 8

right. So, now remember that if a line has a slope of m, the perpendicular line has a slope of -1/m. So, if m=2, what's the perpendicular slope?

Answer 9

-1/2?

Answer 10

yes! nice job. Now can you do the second problem?

Answer 11

yes it will be -1/-3

Answer 12

right, which is 1/3.

Answer 13

what about the last problem?

Answer 14

5/7?

Answer 15

you forgot the negative.

Answer 16

why do we put the negative

Answer 17

its a positive number

Answer 18

for a line with slope m, the perpendicular slope is -1/m. So the perpendicular always has opposite sign as the original line.

Answer 19

ok thank you