tolong bantuin sya ya, kakak, abang. plis bgt. nomor 7 dan 8 ya.

7. 3x+3=-2x+18
3x+2x=18-3
5x=15
x=15÷5
x=3
8. 2(2x+1+x-2) = 40
2(2x+x+1-2) = 40
2(3x-1) = 40
6x-2 = 40
6x =40+2
6x = 42
x = 42÷6
× = 7
Luas : p×l
P = (2×7)+1 = 15
l = 7-2 = 5
Luas : 15x5 = 75

K persegi panjang = 2(p+l)
40 = 2[(2x+1)+(x-2)]
40 = 2[(2x+x+1-2)]
40 = 2[3x-1]
40 = 6x-2
6x = 40+2
6x = 42
x = 42/6
x = 7

Panjang = 2x+1 = 2(7)+1 = 15cm
Lebar = x-2 = 7-2 =5

Luas persegi panjang = p×l= 15×5= 75