Question

The length of a rectangle is 5 cm less than twice its width. The perimeter of the rectangle is 80 cm. What are the dimensions of the rectangle. Help?

Answer 1

@AriPotta Do you think you are able to help me with this? :)

Answer 2

P = 2L + 2W
L = 2W - 5

substitute 2W - 5 for L in the perimeter formula:

80 = 2(2W - 5) + 2W

Answer 3

solve for W

Answer 4

So..80 = 4w - 10 + 2W?

Answer 5

yes. now try to get W by itself

Answer 6

Would I minus the 2W from the 4W?

Answer 7

Oh wait nvm

Answer 8

no, you would add them since they're both positive

Answer 9

80 = -10 + 6W?

Answer 10

yes, good job far :) a few more steps left

Answer 11

good job so far*

Answer 12

Umm..Would I take away 6 from both sides or add ten to both sides? I feel like I should take away 6.

Answer 13

add 10

Answer 14

so 80 = 16w?

Answer 15

no you can't add 10 with 6w cuz they're not like terms. you wanna add 10 to both sides. you'd get 90 = 6w

Answer 16

OhhH! 90 divided by 6..Which is 15..So 15 is the answer?

Answer 17

yes :) W = 15
now to get L. L = 2W - 5. substitute 15 for W. L = 2(15) - 5

Answer 18

25?

Answer 19

yup. so your dimensions are 25 by 15

Answer 20

great job :)

Answer 21

YAY! :D Thank you

Answer 22

no problemo