plis jawab yh yg dibuletin pake cara yh

5.
K = 50
2p + 2l = 50
2(2x + 5) + 2(x - 1) = 50
4x + 10 + 2x - 2 = 50
4x + 2x + 10 - 2 = 50
6x + 8 = 50
6x = 50 - 8
6x = 42
x = 42/6
x = 7 cm

6.
x = (y + 35)
x = 15 + 35
x = 50

7.
3(2a + 1) - 4(2a - 3) =5
6a + 3 - 8a + 12 = 5
6a - 8a + 3 + 12 = 5
-2a + 15 = 5
-2a = 5 - 15
-2a = -10
a = -10/-2
a = 5

No. 8 maaf saya belum bisa bantu
Semoga bermanfaat :)