bagaimana cara menyelesaikannya

keliling = 2(p+l)
62 = 2(5x+1+4x+3)
62 = 2(9x+4)
62 = 18x + 8
54 = 18x
3 = x
panjang=5(3)+1=16
lebar=4(3)+3=15

diketahui rumus keliling persegi panjang = 2 (l+p)

maka
62 = 2 (l+p)
l + p = 62/2 = 31

panjang = 5x + 1
lebar = 4x + 3

31 = (5x + 1) + (4x + 3)
31 = 9x + 4
9x = 31 - 4
9x = 27
x = 3

panjang = 5x + 1 = 5(3) + 1 = 16
lebar = 4x + 3 = 4(3) + 3 = 15

jawabannya adalah b