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Diketahui fungsi  dan . Hasil dari  adalah ....

Diketahui fungsi begin mathsize 14px style f open parentheses x close parentheses equals x squared minus 2 x plus 1 end style dan begin mathsize 14px style g open parentheses x close parentheses equals 4 x minus 7 end style. Hasil dari begin mathsize 14px style open parentheses f cross times g close parentheses open parentheses 3 close parentheses end style adalah ....

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Gunakan konsep perkalian dua fungsi.

begin mathsize 14px style open parentheses f cross times g close parentheses open parentheses x close parentheses equals f open parentheses x close parentheses cross times g open parentheses x close parentheses end style

Diketahui fungsi begin mathsize 14px style f open parentheses x close parentheses equals x squared minus 2 x plus 1 end style dan begin mathsize 14px style g open parentheses x close parentheses equals 4 x minus 7 end style.

Akan ditentukan hasil dari begin mathsize 14px style open parentheses f cross times g close parentheses open parentheses 3 close parentheses end style. perhatikan perhitungan berikut.

begin mathsize 14px style table attributes columnalign right center left columnspacing 2px end attributes row cell open parentheses f cross times g close parentheses open parentheses x close parentheses end cell equals cell f open parentheses x close parentheses cross times g open parentheses x close parentheses end cell row blank equals cell open parentheses x squared minus 2 x plus 1 close parentheses cross times open parentheses 4 x minus 7 close parentheses end cell row blank equals cell 4 x cubed minus 7 x squared minus 8 x squared plus 14 x plus 4 x minus 7 end cell row cell open parentheses f cross times g close parentheses open parentheses x close parentheses end cell equals cell 4 x cubed minus 15 x squared plus 18 x minus 7 end cell row cell open parentheses f cross times g close parentheses open parentheses 3 close parentheses end cell equals cell 4 open parentheses 3 close parentheses cubed minus 15 open parentheses 3 close parentheses squared plus 18 open parentheses 3 close parentheses minus 7 end cell row blank equals cell 4 cross times 27 minus 15 cross times 9 plus 54 minus 7 end cell row blank equals cell 108 minus 135 plus 54 minus 7 end cell row cell open parentheses f cross times g close parentheses open parentheses 3 close parentheses end cell equals 20 end table end style 

Jadi, diperoleh nilai begin mathsize 14px style open parentheses f cross times g close parentheses open parentheses 3 close parentheses equals 20 end style.

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