=3/2(2/10.12+2/12.14+...+2/48.50)
=3/2(1/10-1/12+1/12-1/14+...+1/48-1/50)
=3/2(1/10-1/50)
=3/2 . 2/25 =3/25
Đặt phép tính trên là A
Ta có:
A=3/10*12+3/12*14+3/14*16+...+3/48*50
A*2/3=2/10*12+2/12*14+2/14*16+...+2/48*50
A*2/3=1/10-1/12+1/12-1/14+1/14-1/16+...+1/48-1/50
A*2/3=1/10-1/50
A*2/3=2/25
A=2/25:2/3
A=3/25
Vậy A=3/25
Nếu đúng thì k cho mình nha
\(\frac{3}{10.12}+\frac{3}{12.14}+\frac{3}{14.16}+...+\frac{3}{48.50}\)
\(=\frac{3}{2}.\left(\frac{1}{10}-\frac{1}{12}+\frac{1}{12}-\frac{1}{14}+\frac{1}{14}-\frac{1}{16}+...+\frac{1}{48}-\frac{1}{50}\right)\)
\(=\frac{3}{2}.\left(\frac{1}{10}-\frac{1}{50}\right)\)
\(=\frac{3}{2}.\frac{2}{25}\)
\(=\frac{3}{25}\)
3/10.12+3/12.14+3/14.16+...+3/48.50
=3.2/10.12.2+3.2/12.14.2+3.2/14.16.2+...+3.2/48.50.2
=3/2.(2/10.12+2/12.14+2/14.16+...+2/48.50
=3/2.(1/10-1/12+1/12-1/14+1/14-1/16+...+1/48-1/50
=3/2.(1/10-1/50)
=3/2.(5/50-1/50)
=3/2.2/25
=3/25
học tốt nha bạn
