Diketahui f (x) =ax+b, jikaf(2)=18 dan f(5)=33.tentukan rumus fungsi f(x)!

F(2)=2a+b=18 ->b=18-2a
F(5)=5a+b=33
=5a+18-2a= 33
=3a=33-18
=3a= 15
=a=3
b=18-2a -> b=18-2(3) -> b=12
F(x)=3x+12

f(2) = a(2)+b = 18              f(5) = a(5)+b = 33
          2a+b = 18                          5a+b = 33

2a+b = 18 -->x5
5a+b = 33 -->x2
jadiin persamaan linear dua veriabel dulu terus dikurang

jadi gini

10a+5b = 90 - 10a+2b = 66
hasilnya kan 3b = 24 b=8

nah terus f(2) = a(2)+8 =18
= 2a+8 = 18
   2a = 18-8
   2a = 10
   a = 5

berarti rumusnya f(x) = 5x+8