tolong lahh no 21 buat besok pr mtk

keliling
= 70 = 2[(2x+4)+(2x-1)]
= 35 = 4x + 3
= 32 = 4x
= 8 cm = x

panjang
= 2(8) + 4
= 16 + 4
= 20 cm

lebar
= 2(8) - 1
= 16 - 1
= 15 cm

luas
= 20 × 15
= 300 cm²

maaf kalau salah

K = 2 × ( p + l )
70 = 2 × { ( 2x + 4) + ( 2x - 1 )}
70 ÷ 2 = 2x + 2x + 4 - 1
35 = 4x + 3
35 - 3 = 4x
32 = 4x
x = 8

p = 2x + 4 = 2(8) + 4 = 20 cm
l = 2x - 1 = 2(8) - 1 = 15 cm

L = p × l
= 20 × 15
= 300 cm² ( C )