Bagaimana anda mencari nol, jika ada, y = -7x ^ 2-x + 22 menggunakan formula kuadratik?

Jawapan:

`x = - (1 + sqrt (617)) / 14or- (1-sqrt (617)) / 14`

`x = -1.846 atau 1.702`

Penjelasan:

Diberikan `ax ^ 2 + bx + c`, nol diberikan oleh:

`x = (- b + -sqrt (b ^ 2-4ac)) / (2a)`

`a = -7`

`b = -1`

`c = 22`

`x = (1 + -sqrt ((- 1) ^ 2-4 (-7) (22))) / (2 (-7))`

`x = (1 + -sqrt (1 + 616)) / - 14`

`x = - (1 + -sqrt (617)) / 14`

`x = - (1 + sqrt (617)) / 14or- (1-sqrt (617)) / 14`

`x = -1.846 atau 1.702`