Question

Write the slope-intercept form of the equation parallel to y = 7x + 2, which passes through the point (1, -3).

Answer 1

@tafkas77

Answer 2

Okay. This one is going to be a LOT like the one we just covered. First things first, though: Do you know what parallel lines have in common?

Answer 3

Yeah I think so.

Answer 4

Well, just to be sure... :) Parallel lines have the SAME slope. So if we're looking for an equation that has a line parallel to the equation they gave you, all we need to have is the same slope! In this case, what would our slope be? (Hint: Look for the "m" in y = 7x + 2)

Answer 5

the m is 7

Answer 6

Perfect. So now we can move on to our list of steps. What should we do first, since we know our slope and our equation (y = mx + b)?

Answer 7

we plug in the slope.

Answer 8

Right. :)

y = 7x + b

Okay, what should our next step look like?

Answer 9

we plug in the x and y intercepts. -3 = 71 + b?

Answer 10

oops -3 +7(1) +b

Answer 11

Correct. :) Now, we have to simplify the equation:

-3 = 7 + b

What happens next?

Answer 12

-3 = 7 + b

Answer 13

oh wait

Answer 14

we get b alone.

Answer 15

Exactly. And how do you do that?

Answer 16

I dont know. im a little stuck.

Answer 17

That's all right. :) Well, to get 'b' alone, you want to CANCEL OUT any numbers that 'b' is with. :)

Let's look at what we've got...

-3 = 7 + b

Well, we need to get rid of 7. We want to banish 7 to the other side of the equation. But how?

Answer 18

i dont know.

Answer 19

We'll add a -7 to both sides, because whatever you do to one side, you do to the other.

-7 - 3 = 7 - 7 + b

Answer 20

7 plus -7 equals zero, so that means 'b' gets a little fresh air, know what I mean? Haha, does this make sense?

Answer 21

yeah it does.

Answer 22

Great! So can you simplify -7 - 3 = 7 - 7 + b

Answer 23

-10 = 0 + b

Answer 24

Perfect. So b = -10. Now we know both the slope (7) and the y-intercept (b). Can you solve the original equation (y = mx + b) now?

Answer 25

so the answer is y= 7 + -10

Answer 26

y = 7 -10

Answer 27

Very close. Hey, whenever you see y = mx + b think of it as y = mx +/- b, okay? :) And leave the x in there, so you're still following the format (like you did last time): y = 7x - 10

Awesome work!

Answer 28

thanks for your help! :D

Answer 29

No problem! (Pun totally intended, hehe) :)