Yang bisa no 2 , mohon bantu jawab !

P = 7y
l = 2y
K = 90

K = 2(p+l)
90 = 2x(7y+2y)
90 = 2 x 9y
90 = 18y
90/18 = y
y = 5

P = 7y = 7 x 5 = 35
l = 2y = 2 x 5 = 10

L = p x l
= 35 x 10
= 350 cm² 

Kel= 2 (P+L)
90= 2 (2x + 7x)
90/2= 9x 
45= 9x
45/9= x
5= x

Panjang= 7x= 7(5)= 35
Lebar= 2x= 2(5)= 10 

Luas persegi panjang 
=P x L
= 35 x 10= 350cm²