Diketahui fungsi f(x) =12/mx + n , f(1) = -4 dan f(3) = - 12. Jika f(x) =x . Tentukan nilai x yang memenuhi

f(x)=12/mx + n
f(1)= 12/m + n = -4
f(3)= 12/3m + n = -12 => 4/m + n = -12

12/m + n = -4
4/m + n =-12
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8/m = 8
m=8/8
m=1

4/m + n = -12
4/1+n=-12
4+n=-12
n=-16

f(x)=12/1x + (-16) 
f(x)=12/x -16