Roboguru

DIketahui ,  dan . Jika nilai , nilai  =....

Pertanyaan

DIketahui f left parenthesis x right parenthesis equals x squared minus 3 x plus 7, g left parenthesis x right parenthesis equals 2 x plus 5 dan h left parenthesis x right parenthesis equals x plus 2. Jika nilai left parenthesis f ring operator g ring operator h right parenthesis left parenthesis a right parenthesis equals 11, nilai a =....

  1. negative 5 over 2 atau 1

  2. negative 7 over 2 atau 1

  3. negative 7 over 2 atau negative 1

  4. 7 over 2 atau 1

  5. 1 half atau negative 1

Pembahasan Soal:

Berdasarkan sifat komposisi fungsi, maka didapatkan :

table attributes columnalign right center left columnspacing 0px end attributes row cell f left parenthesis x right parenthesis end cell equals cell x squared minus 3 x plus 7 end cell row cell left parenthesis f ring operator g right parenthesis left parenthesis x right parenthesis end cell equals cell open parentheses 2 x plus 5 close parentheses squared minus 3 open parentheses 2 x plus 5 close parentheses plus 7 end cell row cell open parentheses f ring operator g ring operator h close parentheses left parenthesis x right parenthesis end cell equals cell open parentheses 2 open parentheses x plus 2 close parentheses plus 5 close parentheses squared minus 3 open parentheses 2 open parentheses x plus 2 close parentheses plus 5 close parentheses plus 7 end cell row blank equals cell open parentheses 2 x plus 4 plus 5 close parentheses squared minus 3 left parenthesis 2 x plus 4 plus 5 right parenthesis plus 7 end cell row blank equals cell open parentheses 2 x plus 9 close parentheses squared minus 3 open parentheses 2 x plus 9 close parentheses plus 7 end cell row blank equals cell 4 x squared plus 36 x plus 81 minus 6 x minus 27 plus 7 end cell row blank equals cell 4 x squared plus 36 x minus 6 x plus 81 minus 27 plus 7 end cell row blank equals cell 4 x squared plus 30 x plus 61 end cell end table

Maka :

table attributes columnalign right center left columnspacing 0px end attributes row cell left parenthesis f ring operator g ring operator h right parenthesis left parenthesis a right parenthesis end cell equals 11 row cell 4 a squared plus 30 a plus 61 end cell equals 11 row cell 4 a squared plus 30 a plus 61 minus 11 end cell equals 0 row cell 4 a squared plus 30 a plus 50 end cell equals 0 row cell 2 a squared plus 15 a plus 25 end cell equals 0 row cell left parenthesis 2 a plus 5 right parenthesis left parenthesis a plus 5 right parenthesis end cell equals 0 end table

Maka nilai dari a adalah negative 5 atau negative 5 over 2

Oleh karena itu, tidak ada jawaban yang benar

Pembahasan terverifikasi oleh Roboguru

Terakhir diupdate 06 Mei 2021

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