The perimeter is the sum of all of the sides

perimeter = length + width + length + width = 2*(length + width)

perimeter = 2*((9 + 2*width) + width) (we know length is 9 more than twice width)

60 = 2*(9 + 3*width) (combine terms inside parentheses)

30 = 9 + 3*width (divide by 2)

21 = 3*width (subtract 9)

7 = width (divide by 3)

9 + 2*width = length = 9 + 2*7 = 23

The rectangle is 9 meters wide and 23 meters long.

perimeter = length + width + length + width = 2*(length + width)

perimeter = 2*((9 + 2*width) + width) (we know length is 9 more than twice width)

60 = 2*(9 + 3*width) (combine terms inside parentheses)

30 = 9 + 3*width (divide by 2)

21 = 3*width (subtract 9)

7 = width (divide by 3)

9 + 2*width = length = 9 + 2*7 = 23

The rectangle is 9 meters wide and 23 meters long.