1/48000

2/chịu

mik cũng có câu hỏi như thế này ,các bn giải thik giúp mik đc ko

=???????????

tinh nhanh 2 bai nay giup mk di ma cac ban oi

\(\frac{2,4\times1994\times2+1,6\times3996\times3+1,2\times4010\times4}{3+7+11+...+95+99-275}\)

\(=\frac{0,2\times6\times2\times2\times997\times2+0,2\times8\times6\times666\times3+0,2\times6\times2\times2005\times4}{\left(99+3\right)\times49:2-275}\)

\(=\frac{0,2\times6\times8\times997+0,2\times8\times6\times666\times3+0,2\times6\times8\times2005}{2499-275}\)

\(=\frac{0,2\times6\times8\times\left(997+666\times3+2005\right)}{2224}\)

\(=\frac{0,2\times2\times3\times8\times\left(997+1998+2005\right)}{8\times2\times0,2\times695}\)

\(=\frac{3\times\left(2995+2005\right)}{695}\)

\(=\frac{3\times5000}{695}=\frac{3\times1000\times5}{5\times139}\)

\(=\frac{3\times1000}{139}=\frac{3000}{139}\)

b)  3+7+11+15+...+95+99-27

= (3+99)x49-27

=4998-27

=4971

360125

6177

\(2,4\times1994\times2+1,6\times3996\times3+4,8\times4010\)
\(=4,8\times1994+4,8\times3996+4,8\times4010\)
\(=4,8\times\left(1994+3996+4010\right)\)
\(=4,8\times10000=48000\)

=4 x 1994 + 48 x 3996+48 x 4010

= 4 x 1994 + 48 x ( 3996+4010) 

 = 4 x 1994 + 48 x 8006

=7976 + 384288

= 392264

                                                                          k cho mình nha!

 BÚ