pleeeasee kakak,abang,adek,tolong bantuinn pake caranya,mau dilumpulin bsk

21.
X1 = 2
Y1 = -7
m = -¾

y-y1 = m(x-x1)
y-(-7) = -¾(x-2)
4(y+7) = -3(x-2)
4y + 28 = -3x +6
3x + 4y = 6-28
3x + 4y = -22
jawaban : D

22.
5x-2y = 19
2x+4y = -2 (÷2) >>> x+2y = -1 >>> x = -(2y+1)
5(-2y-1) -2y = 19
-10y -5 -2y = 19
-(10+2)y = 19+5
-12y = 24
y = -2
x = -(-4+1) = 3

>>> 4x + 3y = 4(3) + 3(-2) = 12-6 = 6
jawaban : A

23.
s + m = 105
s = 105-m
2s + 4m = 300
2(105-m) + 4m = 300
(4-2)m = 300-210
2m = 90
m = 90/2
m = 45
s = 105-45 = 60

perolehan yang parkir
= (45x5.000) + (60x2.000)
= 225.000 + 120.000
= 345.000
jawaban : B