Question

Suatu fungsi ditentukan dengan rumus f(x) =px + q. jika f(4) = 26 dan f(6) =40, maka nilai f(3) adalah

Answer 1

F(x) = px +q
f(4) = p(4) +q = 26
       = 4p +q = 26
f(6) = p(6) +q = 40
       = 6p +q = 40

4p +q = 26
6p +q = 40    -
  -2p = -14
   p = -14/-2
   p = 7

4p +q = 26
4(7) +q = 26
21 +q = 26
q = 26 -21
q = 5

f(x) = 7x +5
f(3) = 7(3) +5
       = 21 +5
       = 26

Itu jawabannya.

Answer 2

f(x) = px +q
f(4) = p(4) +q = 26
       = 4p +q = 26
f(6) = p(6) +q = 40
       = 6p +q = 40

4p +q = 26
6p +q = 40    -
  -2p = -14
   p = -14/-2
   p = 7

4p +q = 26
4(7) +q = 26
28 +q = 26
q = 26 -28
q = -2

f(x) = 7x - 2
f(3) = 7(3) - 2
       = 21 -2
       = 19