Tolong dijawab ya, dengan caranya. Terimakasih..

Bab Bangun Datar
Matematika SMP Kelas VII

a] keliling = 2 . (p + l)
                = 2 . (2x + 1 + x - 2)
                = 2 . (3x - 1)
                = (6x - 2) cm

b] keliling = 6x - 2 = 60
6x = 60 + 2
x = 62/6
x = 10 2/6 cm
x = 10 1/3 cm

c] p = 2x + 1
       = 2 . 62/6 + 1
       = 62/3 + 3/3
       = 65/3 cm
        = 21 2/3 cm

l = x - 2
l = 10 1/3 - 2
l = 8 1/3 cm