f(x) = ax + b, jika f(1) = 3, f(2) = 5, maka f(5) sama dengan

FUNGSI

● Alternatif 1
f(x) = ax + b
f(1) = a(1) + b
3 = a + b
a + b = 3 ...... (1)

f(2) = a(2) + b
5 = 2a + b
2a + b = 5 ...... (2)

dari (1) dan (2)
a + b = 3
2a + b = 5
_________ __
-a = -2
a = 2

a+b = 3
b = 3 - a
b = 3-2
b = 1

f(x) = 2x + 1
f(5) = 2×5 + 1
f(5) = 11

● Alternatif 2

(2-1)f(x) = (5-3)x + (2×3 - 5×1)
f(x) = 2x + 6 - 5
f(x)= 2x + 1
sehingga
f(5) = 2×5 + 1
f(5) = 10+1
f(5) = 11

a + b = 3
2a + b = 5
____________ _
-a = -2
a = 2

a + b = 3
2 + b = 3
b = 1

f(x) = ax + b
f(x) = 2x + 1
f(5) = 2(5) + 1
f(5) = 10+1
f(5) = 11

___________
#Semoga bermanfaat ^_^