Suatu fungsi f dirumuskan f(x)=ax+b. jika f(-2)= 30 Dan f (3)=50 tentukan :

Jawaban:

•f(-2) = 30

f(-2) = a(-2)+b

30 = -2a+b…..(1)

•f(3) = 50

f(3) = a(3)+b

50 = 3a+b…….(2)

•eliminasi (1) dan (2)

-2a+b =30

3a+b = 50 _

-5a = -20

a = -20/-5

a = 4

•subtitusi nilai a ke (1)

-2a+b = 30

-2(4)+b = 30

-8+b = 30

b = 30+8

b = 38

f(x) = ax+b

f(x) = 4x+38

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