f(x)=ax+b f(-1)=2 f(2)=11 Tentukan rumus fungsinya (pakai cara)

f(x) = ax + b

f(-1) = 2
a(-1) +b = 2
-a + b = 2..........(1)
f(2) = 11
a(2) +b = 11
2a + b = 11 ..........(2)

eliminasi (1) (2)
-a + b = 2
2a + b = 11
________-
-3a = -9
a = -9/-3
a = 3
substitusi a = 3 ke persamaan (1)
-a + b = 2
-(3) + b = 2
b = 2 + 3
b = 5

maka fungsinya f(x) = 3x + 5