Question

Diketahui f(X) = ax - b jika f(-2) =2 dan f(7) = -70 nilai a+b adalah....

Answer 1

F(x) = ax-b
f(-2) = a(-2) - b
2 = -2a-b ← pers. 1

f(7) = a(7)-b
-70 = 7a-b ← pers. 2

2 =-2a-b
-70 = 7a-b
dikurang
72 = -9a
a = 72:-9
a= -8

2= -2a-b
2= -2(-8)-b
2= 16-b
b = 16-2
b= 14

Jadi nilai a + b = -8 + 14 = 6

Answer 2

F(x) = ax - b
f(-2) = 2
f(7) = -70

-2a+b = 2
7a+b = -70 -
   -9a = 72
      a = 72
           -9
      a = -8
2a+b = -2
2.-8+b = -2
        b = -2 - (-16)
        b = -2 +16
        b = 14
nilai a+b = -8 + 14
             = 6