Question

Suatu persegi kelilingnya (40+3x)cm,jika panjang sisinya (x+3),maka luas perseginya..??

Answer 1

Kel = 4 . s
40+3x = 4 . ( x+3)
40 + 3x = 4x + 12
40 - 12 = 4x - 3x
28 = x

s = 28 + 3 = 31

Luas = 31 . 31 = 961

Answer 2

         K = s × 4
40 + 3x = (x + 3) × 4
40 + 3x = 4x + 12
 3x - 4x = 12 - 40
        -x = -28
         x = 28

s = x + 3
   = 28 + 3
   = 31

L = s × s
   = 31 cm × 31 cm
   = 961 cm²