Question

[Shizuka Chan]

Tìm x thuộc Z biết:

a) 3. ( 2 - x ) +  5 . (x - 6) = -98

b) (x2 - 13 ). ( x² - 17 ) < 0

Answer 1

[Trần Song Linh Linh]

a) 3 . ( 2 - x ) + 5 . ( x - 6 ) = -98

    6 - 3x + 5x - 30             = -98

    6 + 2x -30                     = -98

    6 + 2x                          = -98 + 30

    6 + 2x                          = -68

    2x                                = -68 -6

    2x                                = -74

    x                                  = -74 : 2

    x                                  = -37