Roboguru

Jika maka nilai

Jika begin mathsize 14px style open square brackets table row 4 1 row 3 a end table close square brackets open square brackets table row cell negative 1 end cell a row cell 2 a plus b end cell 7 end table close square brackets equals open square brackets table row 1 15 row 7 20 end table close square brackets end style maka nilai begin mathsize 14px style b equals.... end style 

  1. begin mathsize 14px style negative 2 end style 

  2. begin mathsize 14px style negative 1 end style 

  3. begin mathsize 14px style 0 end style 

  4. begin mathsize 14px style 1 end style 

  5. begin mathsize 14px style 2 end style 

Jawaban:

Perhatikan perhitungan berikut.

begin mathsize 14px style table attributes columnalign right center left columnspacing 2px end attributes row cell open square brackets table row 4 1 row 3 a end table close square brackets open square brackets table row cell negative 1 end cell a row cell 2 a plus b end cell 7 end table close square brackets end cell equals cell open square brackets table row 1 15 row 7 20 end table close square brackets end cell row cell open square brackets table row cell 4 cross times open parentheses negative 1 close parentheses plus 1 cross times open parentheses 2 a plus b close parentheses end cell cell 4 cross times open parentheses a close parentheses plus 1 cross times 7 end cell row cell 3 cross times open parentheses negative 1 close parentheses plus a open parentheses 2 a plus b close parentheses end cell cell 3 cross times open parentheses a close parentheses plus a cross times 7 end cell end table close square brackets end cell equals cell open square brackets table row 1 15 row 7 20 end table close square brackets end cell row cell open square brackets table row cell negative 4 plus 2 a plus b end cell cell 4 a plus 7 end cell row cell negative 3 plus 2 a squared plus a b end cell cell 10 a end cell end table close square brackets end cell equals cell open square brackets table row 1 15 row 7 20 end table close square brackets end cell end table end style

Dengan menggunakan konsep kesamaan matriks tentukan terlebih dahulu nilai begin mathsize 14px style a end style dari elemen matriks baris ke-2 kolom ke-2, diperoleh:

begin mathsize 14px style table attributes columnalign right center left columnspacing 2px end attributes row cell 10 a end cell equals 20 row a equals cell 20 over 10 end cell row a equals 2 end table end style 

Substitusi nilai begin mathsize 14px style a equals 2 end style ke elemen matriks baris ke-1 kolom ke-1, diperoleh:

begin mathsize 14px style table attributes columnalign right center left columnspacing 2px end attributes row cell negative 4 plus 2 a plus b end cell equals 1 row cell negative 4 plus 2 open parentheses 2 close parentheses plus b end cell equals 1 row cell negative 4 plus 4 plus b end cell equals 1 row b equals 1 end table end style 

Jadi, jawaban yang tepat adalah D.

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