kakak tolong aku dong isi nomer 2 samapi 5 kak plissss bsk dikumpulin

3) f(x) = 2px + q
f(-3) = 2p(-3) + q = - 6p + q = - 19
f(4) = 2p(4) + q = 8p + q = 9
----------------------------------------------(-)
- 14p = - 28
p = 2
subtitusi
- 6p + q = - 19
- 6(2) + q = - 19
- 12 + q = - 19
q = - 19 + 12
q = - 7
f(x) = 2px + q
f(x) = 2(2)x - 7 = 4x - 7
f(-5) = 4(-5) - 7 = - 20 - 7 = - 27
f(12) = 4(12) - 7 = 48 - 7 = 41

4) 2x + y = 8
y = - 2x + 8
m = - 2
gradien saling tegak lurus
m1 . m2 = - 1
- 2 . m2 = - 1
m2 = ½
pers garis
y - y1 = m ( x - X1 )
y + 2 = ½ ( x - 4 )
y = ½ x - 2 - 2 ( dikali 2)
2y = x - 8
2y - x + 8 = 0

5) misal
penghapus = x
buku = y
3x = y
4y + 3x = 12.000
4(3x) + 3x = 12.000
12x + 3x = 12.000
15x = 12.000
x = 800
jadi harga 1 penghapus = 800