Đáp án:
Giải thích các bước giải:
A=5/4.5+5/5.6+5/6.7+...+5/160.101
A=1/4-1/5+1/5-1/6+1/6-1/7+...+1/160+101
A=1/4+0+0+0+...+1/160.101
A=1/4+1/160.101
A=1/4+1/32.101
A=1/4+101/32
A=109/32
B=1/3.5+1/5.7+1/7.9+...+1/133
2B=1/3-1/5+1/5-1/7+1/7-1/9+...+1/133
2B=1/3+0+0+0+...+1/133
B=2:(1/3+1/133)
B=2:136/199
B=199/68