Suatu fungsi dinyatakan dengan f(x) = ax + b.  Jika f(2) = 5 dan f(-2) = -3 maka nilai f(-5) = ... a. -10 b. -9 c. 10 d. 11

MAPEL = MATEMATIKA
KELAS = 8
BAB = RELASI & FUNGSI

diketahui =
rumus fungsi f(x) = ax + b
f(2) = 5
f(-2) = -3

ditanya = nilai f(-5) ??

f(x) = ax + b
f(2) = 2a + b = 5

f(x) = ax + b
f(-2) = -2a + b = -3

eliminasi nilai b
2a + b = 5
-2a + b = -3
__________-
4a = 8
a = 8/4
a = 2

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

rumus fungsi :
➡ f(x) = ax + b
➡ f(x) = 2x + 1

nilai f(-5) :
➡ f(-5) = 2x + 1
➡ f(-5) = 2(-5) + 1
➡ f(-5) = -10 + 1
➡ f(-5) = -9

semoga membantu