Question

The area of a rectangle is 140. The length is one less than three times the width. Find the length and width.

Answer 1

Let's say that the width=w and the length=l
The problems says that l=3w-1.
You know that the area of the rectangle is lw
(3w-1)(w)=Area
The problem says that the area of the rectangle is 140
(3w-1)(w)=140
Solve.

Answer 2

So I would go 3w-3(w)=140?
Where do I go from there?

Answer 3

(3w-1)(w)=140, actually.
Then you would distribute the w..... (do it and report back)

Answer 4

I am not quite sure how to distribute that?

Answer 5

@Grazes

Answer 6

Can you distribute 3(x+2)?

Answer 7

3x+6

Answer 8

@Grazes

Answer 9

Do you know what x*x=?

Answer 10

Is it 3w-1w=140?

Answer 11

So basically, you distribute it the same way:
w(3w-1)
(3w*w)-(1*w)
\[3w^2-w=140\]

Answer 12

Then, you want to move all the terms to one side so you can factor for the roots\[3w^2-w-140=0\]
Then, you have 2 choices for factoring: factoring by grouping and the quadratic equation. Which did you learn in class?

Answer 13

I'm taking this class online as a refresher course. I don't remember which one we did.
@Grazes

Answer 14

Let's use the quadratic equation: