tolong aku cari ini 1 sampai 12

1. PQR=180°-(120°+45°)
=180°-165°
=15°

2.ABC=1/2×a×t
324=1/2×36t
648=36t
t=18 cm=AB

3. 2x+y<\6000

4. x+5=3x-7
5+7=3x-x
12 = 2x
x = 6

5. -2x < 2x-4
-2x-2x < -4
-4x < -4
x < 1