The length of a rectangle is 9 cm more then half the width. Find the length of the perimeter is 60cm

length = 1/2 w+9

perimeter = 60 = 2 (l+w)

substitute in for length

60 = 2 (1/2 w + 9 + w)

60 = 2 (3/2 w + 9)

distribute

60 = 3w + 18

subtract 18 from each side

42 = 3w

divide by 3 on each side

14 = w

length = 1/2 w + 9

length = 1/2 (14) + 9

7 + 9

16cm