Question

Fungsi f dirumuskan f(x) = ax + b dengan a dan b bilangan bulat. jika f(2) = -11 dan f(-2) = 1, maka nilai f(4) + f(9) adalah

Answer 1

F(x) = ax +b
f(2) = a(2) +b = -11
      = 2a +b    = -11

f(x) = ax +b
f(-2) = a(-2) +b = 1
       = -2a +b    = 1

2a +b = -11
-2a +b = 1 +
      2b = -10
       b  = -10 / 2
       b  = -5

2a +b = -11
2a +(-5) = -11
2a          = -11 +5
2a          = -6
a            = -6 / 2
a            = -3

f(x) = ax +b
f(4) = -3(4) +(-5)
     = -12 +(-5)
     = -17

f(x) = ax +b
f(9) = -3(9) +(-5)
     = -27 +(-5)
     = -32

f(4) +f(9)
-17 +(-32)
-49

Answer 2

F(2)=a2+b=-11
f(2)=2a+b=-11

f(-2)=a.-2+b=1
f(-2)=-2a+b=1

2a+b=-11
-2a+b=1. -
4a=-12
a=-3

2a+b=-11
2.-3+b=-11
-6+b=-11
b=-5

f(x)=-3x-5

f(4)=-3.4-5
-12-5
-17

f(9)=-3.9-5
-27-5
-32

-17-32=-49