các cậu trả lời giúp mình đi

a.1025

mk chịu câu b

*** mk nha

1 a) (x+ 1) + (x + 2 ) + (x + 3) + ... + (x + 100) = 205550 (100 cặp)

=> (x + x + ... + x) + (1 + 2 + 3 + ... + 100) = 205 550 

      100 số hạng x       100 số hạng

=> 100.x + 100 . 101 : 2 = 205 550 

=> 100.x + 5050              = 205 550

=>  100 . x                      = 205 550 - 5050

=>  100 . x                      = 200500

=>           x                      = 200500 : 100

=>           x                      = 2005

\(a,\frac{2}{3}+\frac{1}{2}+\frac{1}{6}=\frac{4}{6}+\frac{3}{6}+\frac{1}{6}=\frac{8}{6}=\frac{4}{3}\)

\(b,\frac{5}{12}+\frac{5}{6}-\frac{3}{4}=\frac{5}{12}+\frac{10}{12}-\frac{9}{12}=\frac{6}{12}=\frac{1}{2}\)

a) 2/3 + 1/2 + 1/6 =  4/6 + 3/6 +  1/6 = 7/6 + 1/6 = 8/6 = 4/3 

 b) 5/12 + 5/6 - 3/4 = 5/12 + 10/12 - 9/12 = 15/12 - 9/12 = 6/12 = 1/2

 c) 1/3 x 3/5 x 2/5 = 3/15 x 2/5 = 6/75  = 2/25

 d) 15/16 : 3/8 x 3/4 = 15/16 x 8/3 x 3/4 = 1/10 x 3/4 = 3/40 

8 x 12 x 32 + 4 x 27 x 24 + 41 x 6 x 16

=96 x 32 + 96 x 27 + 96 x 41

=96 x (32 + 27 + 41)

= 96 x 100

=9600

A = 8 × 12 × 32 + 4 × 27 × 24 + 41 × 6 × 16

A = 8 × 12 × 32 + 4 × 24 × 27 + 6 × 16 × 41

A = 96 × 32 + 96 × 27 + 96 × 41

A = 96 × (32 + 27 + 41)

A = 96 × 100

A = 9600

a:Sửa đề: 1x3+2x4+...+99x101

\(=1\times\left(1+2\right)+2\times\left(2+2\right)+\cdots+99\times\left(99+2\right)\)

\(=\left(1\times1+2\times2+\cdots+99\times99\right)+2\times\left(1+2+\cdots+99\right)\)

\(=\frac{99\times\left(99+1\right)\times\left(2\times99+1\right)}{6}+2\times\frac{99\times100}{2}\)

\(=\frac{99\times100\times199}{6}+99\times100=33\times50\times199+99\times100\)

\(=33\times50\times\left(199+3\times2\right)=33\times50\times205=338250\)

b: \(\frac89\times\frac{15}{16}\times\ldots\times\frac{2499}{2500}\)

\(=\left(1-\frac19\right)\times\left(1-\frac{1}{16}\right)\times\ldots\times\left(1-\frac{1}{2500}\right)\)

\(=\left(1-\frac13\right)\times\left(1-\frac14\right)\times\ldots\times\left(1-\frac{1}{50}\right)\times\left(1+\frac13\right)\times\left(1+\frac14\right)\times\ldots\times\left(1+\frac{1}{50}\right)\)

\(=\frac23\times\frac34\times\ldots\times\frac{49}{50}\times\frac43\times\frac54\times\ldots\times\frac{51}{50}=\frac{2}{50}\times\frac{51}{3}=\frac{17}{25}\)

Bài 2:

a,4x25x0,25x\(\frac{1}{5}\) x \(\frac{1}{2}\) x 2

 =4x25x0,25x0,2x0,5x2

 =(4x0,25)+(25x0,2)+(0,5x2)

 =      1     +     5             1

 =7

X + 1/2 + X + 1/4 + X + 1/8 + X + 1/8 +X +1/16 

= X + 8/16 + X + 4/16 + X + 2/16 + X + 2/16 +X + 1/16 

= X + ( 8/16 + 4/16 + 2/16 + 2/16 )  + X +1/16 

= X + 1 + X + 1/16 

= X + ( 1 + 1/16 ) 

=  X + 1 VÀ 1/16 

ra nhiều thế

a/b nhân 4 cộng 1/6 = 17/6 số phải tìm là bao nhiêu