Diketahui rumus fungsi dari f(x) =ax+b,f(1)=-4, dan f(-1) =-10,maka nilai f(2)adalah

Diketahui :
f(x) = ax + b
f(1) = -4
f(-1) = -10

Ditanya :
f(2)?

Jawab :
f(x) = ax + b
f(1) = a(1) + b
-4 = a + b

f(-1) = ax + b
f(-1) = a(-1) + b
-10 = -a + b

a + b = -4
-a + b = -10
_________ –
2a = 6
a = 3

a + b = -4
3 + b = -4
b = -7

f(x) = ax + b
f(x) = 3x – 7

f(x) = 3x – 7
f(2) = 3(2) – 7
f(2) = 6 – 7
f(2) = -1