tolong jawab nomor 20 dan 22

20.) garis q (3,0) dan ( 0,-2)
m = -2-0/0-3 = 2/3
m(p)= -3/2
garis p melalui (3,0), persamaan :
y-0 = -3/2 (x-3)
2y = -3 (x-3) (A.)
2y = -3x + 9

22.) mobil = x, motor = y
3x + 5y = 17 (x4) 12x + 20y = 68
4x + 2y = 18 (x3) 12x + 6y = 54 (di eleminasi)
14y = 14
y = 1 (1 motor = Rp.1000)

4x+2y=18
4x = 18-2
x= 16:4 = 4 ( 1mobil = Rp.4000)

20x + 30y = (20x4000) + (30x1000)
=80.000 + 30.000
= Rp.110.000 (C.)