Question

Finding the y-intercept of 7x-y = -14

Answer 1

First you need to put this into y=ax+b format.

Do you know how to do that?

Answer 2

Yes, I do. I've gotten to the point of where -y = -14 + -7x. The x equals zero and that's where I've gotten stuck.

Answer 3

I think the problem is that your plus sign is throwing you off :)

When i rearrange it i get -y=-7-14.

Now, we are going to have to isolate the y. Do this by dividing each side by -1.

-y/-1 = -7-14/-1

What do you get after this?

Answer 4

Excuse me, it would actually be

-y/-1 = -7x-14/1

Answer 5

7 x 0 is 0. That's what threw me off because there was a negative sign in front of the 0. That's definitely what confused me. (:

Answer 6

to find the y intercept, substitute 0 in for x

Answer 7

Yes, the next step is to substitute the 0 for x. *cough cough*....

y=7(0)+14
=0+14
= ?

and that is your answer :)

Answer 8

Excuse me, it would actually be

-y/-1 = -7x-14/1

Answer 9

The 14 was negative, though. I probably sound foolish.

Answer 10

just sub 0 in for x and you get y = 14

Answer 11

No worries Alivia, we all make mistake sometimes!

Answer 12

The equation
y = mx + b
is the slope-intercept form of the equation of a line.

If you write the equation of a line in that form, you can readily find the slope
and the y-intercept without any further calculations.
The slope is m and the y-intercept is b.

If you are asked for the y-intercept of an equation, solve the equation for y, and put in the slope intercept form. Then you can tell quickly what the y-intercept is.

In this problem, you were asked to find the y-intercept of
7x - y = -14

You need to solve the equation for y:

First, subtract 7x from both sides, and place the -7x to the left of the -14:

7x - y = -14
-7x -7x
--------------------
-y = -7x - 14

Since you now have -y, but you want y, you can multiply both sides by -1.

-1(-y) = (-1)(-7x) - (-1)(14)

y = 7x + 14

From the slope-intercept form you can immediately conclude that the y-intercept is 14.
(You can also conclude that the slope is 7, but you were not asked that.)

Answer 13

Thank you guys so, so much! You've been an amazing help! And oh my goodness, that's very detailed, but it helps a lot. Thank you! <3

Answer 14

You're welcome.