Question

what equation of the line passes through the point (-1, 7) and perpendicular to y = -1/4x - 5

Answer 1

Do you know how to start?

Answer 2

look for a similar slope...?

Answer 3

Well here. Do you know what the perpendicular slope of \[y=-\frac{1}{4}-5\]

Answer 4

*\[y=\frac{-1}{4}x-5\]

Answer 5

the slope would be -1\[\frac{ -1 }{ 4 }\]

Answer 6

Not exactly. When finding the perpendicular slope you have to take the negative reciprocal. For example the perpendicular slope of 2 would be -1/2

Answer 7

so this would be 4? or 4/1?

Answer 8

Yup! :)

4/1 is the same as 4

Answer 9

So you could just use 4

Answer 10

so how do I determine b?

Answer 11

Now that we have the slope we can find the equation.
Do you know the point-slope formula?

Answer 12

y-y1= m(x-x1)

Answer 13

Correct, and you re given a set of points correct?

Answer 14

(-1,7)

Answer 15

So now we have m=4, x1=-1, and y1=7. Guess what we do next?

Answer 16

plug it into the formula

Answer 17

Yup!

Answer 18

Tell me what you come up with.

Answer 19

y = 4x + 3

Answer 20

Good job! See it wasn't so hard now was it? :)

Answer 21

no. thanks (:

Answer 22

Yup, anytime!