Question

The width of a rectangle is 3x – 3. Its perimeter is 10x + 6. Find the length of the rectangle.

Answer 1

Step-by-step explanation:

The first possibility

2(width) + 2(length) = perimeter

2(3x-3) + 2(length) = 10x+6

6x - 6 + 2(length) = 10x+6

2(length) = 4x + 12

length = 2x + 6

The second possibility.

rondhesha chodado in The width of a rectangle is 3x – 3. Its perimeter is 10x + 6. Find the length of the rectangle.

So you have the perimeter, P, can be found by doing u+u+v+v.

Simplifying gives:

P=2u+2v.

You are given the width is (3x-3).  Choose this to be u or v but not both.

Perimeter is given a (10x+6).

Let's plug this in:

(10x+6)=2(3x-3)+2v

We are solving for v.

First step: Distribute where you can:

10x+6=6x-6+2v

Now we want to isolate v.

So we will need to subtract (6v-6) on both sides:

 (10x+6)=2v

- (6x -6)

----------------------

4x+12  =2v

The right hand side contains a factor of 2.

The left hand side does too since 4x+12 can be factored as 2(2x+6).

2(2x+6)=2v

This implies v is 2x+6.

Let's check our work.

We have two sides with measurement 2x+6:  (2x+6)+(2x+6)=4x+12

We have two sides with measurement 3x-3:   (3x-3)+(3x-3)=  6x-6

Let's add those sums to find the perimeter:                             10x+6

That is the intended