Question

[Pham Trong Bach]

Tìm x

a)  2 9 − 7 8 . x = 1 3

b)  4 5 + 5 7 : x = 1 6

Answer 1

[Cao Minh Tâm]

a) 

2 9 − 7 8 . x = 1 3          7 8 . x =   2 9 − 1 3          7 8 . x = − 1 3               x   =   − 1 3 : 7 8               x   =   − 8 21

b)

4 5 + 5 7 : x = 1 6          5 7 : x   =   1 6 − 4 5          5 7 : x   =   − 19 30                 x   =   5 7 : − 19 30                x = − 150 133