Jawabanmu

2014-05-06T08:19:24+07:00
K = 2×(p+l)
70 = 2×(5x + 9 + 2x +5)
70 = 2×(7x + 14)
70= 14x + 28
70-28 = 14x
42 = 14x
3 = x

panjang = 5x + 9 = (5×3) + 9 = 24 cm
lebar     = 2x + 5 = (2×3) + 5 = 11 cm

semoga bermanfaat ya! tolong tandai jwbn ini sebagai yang terbaik! thanks! ;)

2014-05-06T08:20:40+07:00
K = 2 (p + l)
70 = 2 (5x+9 + 2x+5)
70 = 2 ( 7x + 14 )
70 = 14x + 28
70 - 28 = 14x
42 = 14x
3 = x
#panjang = 5x + 9 = 5(3) + 9 = 24
#lebar = 2x + 5 = 2(3) + 5 = 11