Fungsi f ditentukan dengan rumus: f(x)=ax+b,bila f(2)=1danf(4)=7.Maka nilai a+2b adalah

MAPEL = MATEMATIKA
KELAS = 8
BAB = RELASI & FUNGSI

diketahui =
f(x) = ax + b
f(2) = 1
f(4) = 7

ditanya = nilai a + 2b??

f(x) = ax + b
f(2) = 2a + b = 1

f(x) = ax + b
f(4) = 4a + b = 7

eliminasi nilai b
2a + b = 1
4a + b = 7
________-
-2a = -6
a = -6/-2
a = 3

subtitusi nilai a
2a + b = 1
2(3) + b = 1
6 + b = 1
b = 1 - 6
b = -5

nilai a + 2b :
= 3 + 2(-5)
= 3 + (-10)
= 7

semoga membantu