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Persamaan fungsi kuadrat yang memotong sumbu x di (- 3,0) dan (5,0) serta melalui titik ( 2,30) adalah ...

Pertanyaan

Persamaan fungsi kuadrat yang memotong sumbu x di (- 3,0) dan (5,0) serta melalui titik ( 2,30) adalah ...

  1. straight y space equals negative 2 straight x squared space plus 4 straight x space plus 30

  2. straight y space equals negative 2 straight x squared space minus 4 straight x space plus 30

  3. straight y space equals 2 straight x squared space minus 4 straight x space minus 30

  4. straight y space equals 2 straight x squared space minus 4 straight x space plus 30

  5. straight y space equals 2 straight x squared space plus 4 straight x space minus 30

Pembahasan Soal:

straight y space equals space straight a left parenthesis space straight x space minus space straight x subscript 1 space right parenthesis space left parenthesis space straight x space minus space straight x subscript 2 space right parenthesis  straight y space equals space straight a left parenthesis straight x plus 3 right parenthesis left parenthesis straight x space minus space 5 right parenthesis space... space left parenthesis straight i right parenthesis

Grafik fungsi melalui (2,30), maka:

30 space equals space straight a left parenthesis 2 space plus space 3 right parenthesis left parenthesis 2 space minus space 5 right parenthesis space  30 space equals space straight a left parenthesis 5 right parenthesis left parenthesis negative space 3 right parenthesis space  30 space equals space minus space 15 straight a space left right double arrow space straight a space equals negative 2

Substitusikan a equals 2 ke persamaan (i)

straight y space equals negative 2 straight x left parenthesis straight x space plus space 3 right parenthesis left parenthesis straight x space minus space 5 right parenthesis  straight y space equals negative 2 left parenthesis straight x squared space minus space 2 straight x space minus space 15 right parenthesis  straight y space equals space minus space 2 straight x squared space plus space 4 straight x space plus space 30

Pembahasan terverifikasi oleh Roboguru

Terakhir diupdate 22 Desember 2020

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