a) [ 316 – ( 25 . 4 + 16 )] : 8 – 24

=( 316 – 116 ) : 8 – 24 = 200 ∶ 8 – 24 = 25 – 24 = 1

b) | -15| + (-27) + 8 + | - 23|

= 15 – 27 + 8 + 23 = 19

c)  5 8   :   5 6   +   2 2   .   3 3   -   2010 0  =  5 2 + 4 . 27 – 1 = 25 + 108 – 1 = 132

Lời giải:
$y: \frac{1}{8}+y\times 92=20100$

$y\times 8+y\times 92=20100$

$y\times (8+92)=20100$

$y\times 100=20100$

$y=20100:100=201$

-------------------

$y: \frac{1}{25}+y\times 75=25000$

$y\times 25+y\times 75=25000$

$y\times (25+75)=25000$

$y\times 100=25000$

$y=25000:100=250$

c)  5 8 : 5 6 + 2 2 . 3 3 - 2010 0  = 52 + 4 . 27 – 1 = 25 + 108 – 1 = 132

\(12.7+4.21+2.42+6.14+84\)

\(=12.7+4.3.7+2.6.7+6.2.7+12.7\)

\(=5.12.7\)

\(=60.7+420\)

12 . 7 + 4 .21 + 2 . 42 + 6 . 14 + 84

= 84 + 84+ 84 + 84 +84

= 84 . 5

= 420

X = 200

Ta có: S = 1 + 2 + 3 + ... + X ( 1 )

 S = X + X - 1 + ... + 1 ( 2 )

 => ( 1 ) + ( 2 ) = 2S = X + 1 + X + 1 + ... + X + 1 

2S = X( X + 1 )

 => S = X( X + 1 ) : 2

 Ta có: 1 + 2 + 3 + 4 + 5 + ... + x = 20100

=> x( x + 1 ) : 2 = 20100

=> x² + x - 40200 = 0

=> x = 200 hoặc x = -210 ( loại )

Ta có: S = 1 + 2 + 3 + ... + X ( 1 )

 S = X + X - 1 + ... + 1 ( 2 )

 => ( 1 ) + ( 2 ) = 2S = X + 1 + X + 1 + ... + X + 1 

2S = X( X + 1 )

 => S = X( X + 1 ) : 2

 Ta có: 1 + 2 + 3 + 4 + 5 + ... + x = 20100

=> x( x + 1 ) : 2 = 20100

=> x² + x - 40200 = 0

=> x = 200 hoặc x = -210 ( loại )

A. 200

Chọn A

Ta có

\(1+2+3+4+...+x=20100\)

\(\left(x+1\right)\times x\div2=20100\)

\(\left(x+1\right)\times x=20100\times2\)

\(\left(x+1\right)\times x=40200\)

Mà \(40200=201\times200\)

\(\Rightarrow\left(x+1\right)\times x=201\times200\)

\(\Rightarrow x=200\)

Vậy x = 200