diketahuif(x)=ax+bjikaf(2)=5 danf(-5)=-9 maka tentukan lah f(-3)

Diket :
fx = ax+b
f2 = 5
f-5 = =9

Jawab :
f(2) = 2a+b = 5
f(-5) = -5a+b = -9
--------------------------(dikurang)
7a = 14
a = 14/7
a = 2

2a+b = 5
b = 5-2a
b = 5-2(2)
b = 5-4
b = 1

f(-3) = 2x+1
f(-3) = 2(-3)+1
f(-3) = -6+1
f(-3) = -5

maaf jika ad kesalahan :)

Kelas 8 Matematika
Bab Fungsi

f(x) = ax + b

f(2) = 2a + b = 5
f(-5) = -5a + b = -9
.........-------------------- -
7a = 14
a = 14/7
a = 2

2a + b = 5
2 . 2 + b = 5
b = 5 - 4
b = 1

f(x) = 2x + 1

f(-3) = 2 . (-3) + 1
f(-3) = -6 + 1
f(-3) = -5