fungsif ditentukan rumus f (x) =ax=b bila f(2)=1,danf(4)=7,aka nilai a=2b adalah

F(2) = 2a+b = 1
F(4) = 4a+b = 7
————————(kurang)
-2a = -6
a = -6/-2
a = 3

2a+b = 1
b = 1-2(3)
b = 1-6
b = -5

a = 2b???
3 = 2(-5)
3 = -5

Maaf jika ad kesalahan

f(x) = ax+b
f(2) = 2a+b = 1
f(4) = 4a+b = 7
         -2a    = -6
               a = -6 
                     -2
               a = 3

4a+b = 7
4 . 3 + b =7
12 + b = 7
       b = 7 -12 = -5

a+2b
3 + 2 . -5 = -7

jadi jawabannya -7