fungsi f dinyatakan dengan rumus f(x) = ax+b, jika f(2)=12 dan f(-2)=2, maka nilai f(0) adalah...

Jawab :

f(x) = ax + b
f(2) = a(2) + b = 2a + b = 12
f(-2) = a(-2) + b = -2a + b = 2

2a + b = 12
-2a + b = 2
______________ -
4a = 10
a = 2,5

-2a + b = 2
-2(2,5) + b = 2
-5 + b = 2
b = 2 + 5
b = 7

f(x) = ax + b = 2,5x + 7

f(0) = 2,5(0) + 7 = 7

f(x) = ax + b

f(2) = 12
  12 = 2a + b

f(-2) = 2
     2 = -2a + b


12 = 2a + b
  2 = -2a + b
----------------- -
10 = 4a
a = [tex] \frac{10}{4} [/tex]

2a + b = 12
2([tex] \frac{10}{4} [/tex]) + b = 12
5 + b = 12
      b = 12 - 5 = 7

f(0) = [tex] \frac{10}{4} [/tex](0) + 7 = 7