Đáp án:
Giải thích các bước giải:
a)7/2.-9/14.7/3
=7/(-9).7/2.14.3
= 7.(-3).3.7/2.2.7.3
= -21/4
b) (-1/2)^2.7/9+25%.2/9-2 3/4
= 1/4.7/9+25/100.2/9-11/4
= 1/4.7/9+25/100.2/9+-11/4
=1/4.7/9+1/4.2/9+-11/4
= 1/4.(7/9+2/9)+-11/4
= 1/4.9/9+-11/4
= 1/4.1+-11/4
=1/4+-11/4
=-10/4=-5/2
c) (8 12/13-4 3/5) - (3 2/5 -1/13)
= (116/13-23/5)-(17/5-1/13)
= 116/13-23/5-17/5-1/13
=(116/13-1/13)-(23/5-17/5)
= 115/13-6/5
= 575/65-78/65
= 497/65
Chúc bn học tốt!
