Help. Don’t know if in the right category though

[Narwalalpaca12$]

I don’t understand how to do these three problems

 

[Dr.Peterson]

Let's take one problem at a time. Since you haven't said anything about what you do know, I'll have to take a guess and suppose you have learned about variables and writing equations, but don't know where to start.

For #1, I'd start by noticing that we can use W as our single variable, since it tells how to find the length if you know the width. So we define the variable,

W = width of original rectangle in meters​

Then the original rectangle has

width = W m​

length = 3W m​

Now, if we increase the length by 4 m and decrease the width by 1 m, what will the new dimensions be?

width = _____ m​

length = _____ m​

What is the formula for perimeter in terms of length and width?

Use that to write an equation that says the perimeter is 66 m.

Please show your work at least this far, and we can discuss what comes next. (I'll be expecting you to try the other problems entirely on your own so we can see how much you've learned from the first.)

 

[Narwalalpaca12$]

Like this?

 

[Dr.Peterson]

Check your signs, in the original equation as well as in your work. What do "increased" and "decreased" mean? And you made a different mistake in your check!

But some errors seem to have canceled others out, so maybe you just didn't write what you meant ...

 

[Narwalalpaca12$]

I don’t quite understand what your saying

 

[Dr.Peterson]

The problem says,

The length of a rectangle is 3 times the width. If the length is decreased by 4 m and the width is increased by 1 m, the perimeter will be 66 m. Find the dimensions of the original rectangle.​

You wrote:

length: 3x + 4​

width: x - 1​

Is that what it will be after the length is decreased by 4 (from 3x) and the width is increased by 1 (from w)?

After fixing that, just make sure that the signs are correct in each step you write. (This should be something you do routinely, as we all make mistakes; checking what we write is an essential part of getting things right.)