Đáp án:
Giải thích các bước giải:
A = (-6/7 +6/13 -6/29)/( 9/7-9/13+9/29)
A = [6.(-1/7 +1/13 -1/29)]/[-9.(-1/7 + 1/13 -1/29)]
A =6/(-9) =-2/3
B = (2/15 - 2/21 +2/39)/(0.25-5/28+5/52)
B = [2.(1/15 - 1/21 + 1/39)] / [5.(1/20 -1/28 +1/52)]
B = [2.(4/60 - 4/84 + 4/156)] / [5.(3/60 -3/84 +3/156)]
B = [8.(1/60 - 1/84 + 1/156)] / [15.(1/60 -1/84 +1/156)]
B = 8/15