Question

3/1.3+3/3.5+3/5.7+......+3/47.49

Answer 1

1/1-1/3+1/3-1/5+1/5-1/7+...... +1/47-1/49

Answer 2

 3/1.3+3/3.5+3/5.7+......+3/47.49

=1/1-1/3+1/3-1/5+1/5-1/7+........+1/47-1/49

=1/1-1/49

=49/49-1/49

=48/49

Answer 3

= 1 - 1/3 + 1/3 - 1/5 + 1/5 - 1/7 +......+ 1/47 - 1/49

= 1 - 1/49

= 48/49 nha!

*** Ai k mk mk k lại !!***

Answer 4

 3/1.3+3/3.5+3/5.7+...+3/47.49

=3/2(2/1.3+2/3.5+2/5.7+...+2/47.49)

=3/2(1-1/3+1/3-1/5+1/5-1/7+...+1/47-1/49

=3/2(1-1/49)

=3/2.48/49

=72/49