Question

Select the equations that are parallel and perpendicular to y = x + 5 and that pass through the point (-2, -1).

A)parallel: y = -x - 1 perpendicular: y = x + 2 B)parallel: y = x - 1 perpendicular: y = -x + 1 C)parallel: y = x + 1 perpendicular: y = -x - 3 D)parallel: y = 2x - 2 perpendicular: y = -2x - 1

Answer 1

A)parallel: y = -x - 1 perpendicular: y = x + 2
B)parallel: y = x - 1 perpendicular: y = -x + 1
C)parallel: y = x + 1 perpendicular: y = -x - 3
D)parallel: y = 2x - 2 perpendicular: y = -2x - 1

Answer 2

Parallel lines have the same slope, so you can eliminate two options.

Answer 3

does that mean id eliminate d and a?

Answer 4

Yes!

Answer 5

ok now how would i find the right one of b and c?

Answer 6

Perpendicular lines have the negative reciprocal. Which is -1.

Answer 7

Actually you still have 2 choices.

Answer 8

yeah cuz both the two choices left have a negative slope for the perpendicular

Answer 9

Now you have to check if an equation passes through the point (-2,-1).

Answer 10

does this mean my answer is C?

Answer 11

@ParthKohli

Answer 12

Alright, the parallel has same slope while the perpendicular have opposite number and opposite sign of slope. Use this formula
y - y1 = m(x - x1)
y -(-1) = 1(x-(-2))
y=x+3 (parallel)

y-y1 = m(x-x1)
y-(-1) = -1(x-(-2))
y=-x-1

Answer 13

i do not have an answer choice for that one tho, what do i do?

Answer 14

Correct @mumina1999

Answer 15

ok thank you , can i ask one more question?

Answer 16

Ask two..

Answer 17

Sure @mumina1999

Answer 18

What is the equation of the line that passes through the points (-2, 1) and (1, 10)?

3x - y = -7

3x - y = -5

3x - y = 5

x + 3y = -5

Answer 19

Ah, the point slope form would work.

Answer 20

Can you calculate the slope?

Answer 21

Two point form..

Answer 22

let me try, i think point slope is this -
y-y1 = m(x-x1)?

Answer 23

Yes. Can you calculate the slope?

Answer 24

yeah is it -9/3?

Answer 25

Check it once again..

Answer 26

ok

Answer 27

9/3 without the negative?

Answer 28

\[{y_2 - y_1 \over x_2 - x_1}\]Just for a quick reminder.

Answer 29

Yes!

Answer 30

Yep..

Answer 31

thats what i did, ok now wat do i do

Answer 32

Use the equation you have written above..

Answer 33

Now, pick any point.

Answer 34

You have two points; pick any.

Answer 35

Use that point here :

\[y- y_1 = m(x - x_1)\] You know m = 9/3 = ??

Answer 36

y = 3x + 7?

Answer 37

Let me check.\[y -1 = 3(x +3 )\]

Answer 38

That's a 2*

Answer 39

Yes, you're correct.

Answer 40

Is not that right??

Answer 41

ok but which answe choice would i choose becuase the answer choices seem to be in a different form

Answer 42

y = 3x + 7

Rearrange it to form ax + by = c form..

Answer 43

Can you do it??

Answer 44

let me try

Answer 45

Take your time..

Answer 46

3x - y = -7?

Answer 47

Yep..

Answer 48

Sorry, heh

Answer 49

o ok thank you both!!!

Answer 50

yw :)

Answer 51

Welcome dear..

Answer 52

Keep practicing more questions related to this topic..

Answer 53

yeah i will

Answer 54

I forgot to practice and you can see what a duffer I am :P

Answer 55

But those questions must be different from each other..

Ha ha ha..