Question

Suatu fungsi f yang dirumuskan dengan f(x)=ax+b diketahui bahwa f(1) =3 dan f(-3)=11. nilai a dan b berturut-turut adalah.....

Answer 1

F(x) = ax+b
f(1) = a(1)+b
3 = a+b
b = 3-a ........(pers. 1)
f(-3) = a(-3)+b
11 = -3a+b ...(pers. 2)

-3a+b = 11
-3a+(3-a) = 11
-3a+3-a = 11
-4a = 11-3
-4a = 8
4a = -8
a = -8/4
a = -2

a+b = 3
-2 + b = 3
b = 3+2
b = 5

Answer 2

 f(1) = a.3 + b =  3a + b = 3

f(-3)= a.-3 + b = -3a + b = 11 +

                                   2b = 14

                                      b = 7

3a + b = 3

-3a + b = 11 -

        6a = -8

           a = -8/6

            a = -1 1/3