# Thread: equation is the standard form of a line. Solve for y.

1. ## equation is the standard form of a line. Solve for y.

Hello everyone... I'm new here, first post and all...

So I was wondering if someone could help me out with the following equation... I'm using MyMathLab and have exhausted all of my tries, otherwise I wouldn't have asked here... Anyway, here's the equation...

The following equation is the standard form of a line. Solve for y.
3x-9y=18
(Use integers or fractions for any numbers in the expression. Simplify your answer.)

Here's the work that I did...
3x-9y=18
-9y=18-3x
y=18-3x/-9
y=-2-3x/-9
y=-2-3/9x

However, my answer is wrong... Can someone please guide me to what I am doing wrong?

2. ## Re: equation is the standard form of a line. Solve for y.

Originally Posted by WebWired
Hello everyone... I'm new here, first post and all...

So I was wondering if someone could help me out with the following equation... I'm using MyMathLab and have exhausted all of my tries, otherwise I wouldn't have asked here... Anyway, here's the equation...

The following equation is the standard form of a line. Solve for y.
3x-9y=18
(Use integers or fractions for any numbers in the expression. Simplify your answer.)

Here's the work that I did...
3x-9y=18
-9y=18-3x
y=18-3x/-9
y=-2-3x/-9
y=-2-3/9x

However, my answer is wrong... Can someone please guide me to what I am doing wrong?
For starters, you need to use brackets where they are needed, it should be y = (18 - 3x)/(-9), which becomes y = 18/(-9) - [3/(-9)]x. Simplify this.

3. ## Re: equation is the standard form of a line. Solve for y.

Originally Posted by Prove It
For starters, you need to use brackets where they are needed, it should be y = (18 - 3x)/(-9), which becomes y = 18/(-9) - [3/(-9)]x. Simplify this.
A positive...

I see where you're going, but what's really throwing me off is that the problem before it was nearly identical ... and I ended up missing it, so it gave me this one, but not before giving me the answer that it wanted...

Here was the problem and the answer, 4x-6y=18, Final correct answer: y=-3-(2/3)x ... so with that in mind, I did the same math on the new problem, 3x-9y=18, I thought would be: y=-2-(1/3)x

4. ## Re: equation is the standard form of a line. Solve for y.

Originally Posted by WebWired
A positive...

I see where you're going, but what's really throwing me off is that the problem before it was nearly identical ... and I ended up missing it, so it gave me this one, but not before giving me the answer that it wanted...

Here was the problem and the answer, 4x-6y=18, Final correct answer: y=-3-(2/3)x ... so with that in mind, I did the same math on the new problem, 3x-9y=18, I thought would be: y=-2-(1/3)x
Like you said, two negatives gives a positive. So what should you do with " -[3/(-9)] "?

5. ## Re: equation is the standard form of a line. Solve for y.

Make it a positive fraction?

6. ## Re: equation is the standard form of a line. Solve for y.

Originally Posted by WebWired
Make it a positive fraction?
Yes, so what is the answer?

7. ## Re: equation is the standard form of a line. Solve for y.

Originally Posted by Prove It
Yes, so what is the answer?
y=-2(1/3)x ... right?

8. ## Re: equation is the standard form of a line. Solve for y.

Originally Posted by WebWired
y=-2(1/3)x ... right?
I'm sure you mean y = -2 + (1/3)x

9. ## Re: equation is the standard form of a line. Solve for y.

Originally Posted by Prove It
I'm sure you mean y = -2 + (1/3)x
Yes, you are absolutely correct, thank you very much for your assistance...

Wow, being out of school for 23 years could certainly make one have to revive long laid dormant parts of one's brain...