−53 D) ) (0,25)3

81 . - KIEM TRA DS C1 LOP 7 CO BAI MO RONG CHO HS KHA GIOI
KIEM TRA DS C1 LOP 7 CO BAI MO RONG CHO HS KHA GIOI

81 .3

c,

1672:−53+2872:−53

d) ) (0,25)

3

.32; e)

10

15