Question

If the length of the given rectangle is increased by 7 and the width is decreased by 3, what is the rectangle's perimeter

Answer 1

For a given length l and width w, the new perimeter is....

2(l + w) + 8

Explanation:

Currently, the rectangle's perimeter is 2(l + w). You knew that.

Now, the question asked you to change l into l + 7, and w into w - 3. Substitute them, so we get

Perimeter New = 2(l + 7 w - 3) = 2 (l + w + 4)

Then, I chose to "pull out" + 4, so I multiply it with the 2. Hence, we get

Perimeter New = 2 (l + w) + 8