Pertanyaan

Diketahui fungsi f ( x ) = a x + b . Jika f ( − 1 ) = 7 dan f ( 3 ) = − 1 , maka nilai c yang memenuhi f ( c ) = 15 adalah….

Diketahui fungsi $f (x) = a x + b$ . Jika $f (- 1) = 7 dan f (3) = - 1$ , maka nilai c yang memenuhi $f (c) = 15$ adalah….

-7
-5
-2
1
4

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N. Rahayu

Master Teacher

Mahasiswa/Alumni Universitas Negeri Jakarta

Jawaban terverifikasi

Pembahasan

$f left parenthesis x right parenthesis equals a x plus b fraction numerator f left parenthesis negative 1 right parenthesis equals 7 space space space left right arrow negative a plus b equals 7 f left parenthesis 3 right parenthesis space space space equals negative 1 left right arrow space 3 a plus b equals negative 1 over denominator space space space space space space space space space space space space space space space space space space space space space space space space space minus 4 a equals 8 end fraction minus space space space space space space space space space space space space space space space space space space space space space space space space space space space space space space space space space space space space space a equals negative 2 Substitusikan space nilai space a space ke colon minus a plus b equals 7 comma space maka colon minus left parenthesis negative 2 right parenthesis plus b equals 7 b equals 5 Sehingga space fungsinya comma space yaitu colon f left parenthesis x right parenthesis equals negative 2 x plus 5 j a d i comma space n i l a i space c space n y a space a d a l a h colon f left parenthesis c right parenthesis equals negative 2 c plus 5 15 equals negative 2 c plus 5 2 c equals negative 10 c equals negative 5$