a) 85 - ( 3 . 5² - 4 . 3² )

= 85 - ( 3 . 25 - 4 . 9 )

= 85 - ( 75 - 36 )

= 85 - 39

= 46

b) 9 . 2³ - ( 7¹¹ : 7² + 1²⁰¹⁵ + 2016⁰ )

= 72 - ( 7⁹ + 1²⁰¹⁵ + 0 )

= 72 - 40353608

= - 40353536

c) 24 : { 390 : [ 500 - ( 5³ + 49 . 5 )]}

= 24 : [ 390 : ( 500 - 370 ) ]

= 24 : ( 390 : 130 )

= 24 : 3

= 8

d) 2 + 4 + 6 + ... + 1000

Có số số hạng là:

     ( 1000 - 2 ) : 2 + 1 = 500 ( số )

Tổng là:

     ( 1000 + 2 ) . 500 : 2 = 250500

   24 : { 390 : [ 500 - ( 125 + 35 . 7 )]} - 3²

= 24 : { 390 : [ 500 - ( 125 +   245 )]} - 9

= 24 : { 390 : [     500     -      370    ]} - 9

= 24 : { 390 :  130} - 9

= 24 :        3           - 9

= 8          -           9 =    -1

k mik nha, thank nhiều nhiều

\(24:\left\{390-[500-\left(125+35.7\right)]\right\}=2^x\)

\(24:\left\{390-[500-\left(125+245\right)]\right\}=2^x\)

\(24:\left\{390-[500-370]\right\}=2^x\)

\(24:\left\{390-130\right\}=2^x\)

\(24:260=2^x\)

Chỗ này sai đề ạ !

24 : { 390 - [ 500 - ( 125 + 35 . 7 ) ] } = 2^x

2^x = 24 : { 390 - [ 500 - ( 125 + 245 ) ] }

2^x = 24 : { 390 - [ 500 - 370 ] }

2^x = 24 : { 390 - 130 }

2^x = 24 : 260

2^x = 6/65 = ......................

=> Đề sai

63 đây k cho mình đi

mình tính ko ra .

12:{390:[500-(5^3+5.7^2) ] }

=12:{390:[500-(125+245 ) ] }

=12:{390:[500-370] }

=12:{390:130}

=12:3

=4

\(12:\left\{390:\left[500-\left(5^3+5.7^2\right)\right]\right\}\)

\(=12:\left\{390:\left[500-\left(125+5.49\right)\right]\right\}\)

\(=12:\left\{390:\left[500-\left(125+245\right)\right]\right\}\)

\(=12:\left\{390:\left[500-370\right]\right\}\)

\(=12:\left\{390:130\right\}\)

\(=12:3\)

\(=4\)

_Chúc bạn học tốt_

Ta có:

\(12:\left\{390:\left[500-\left(5^3+7^2.5\right)\right]\right\}\)

\(=12:\left\{390:\left[500-125-245\right]\right\}\)

\(=12:\left(390:130\right)\)

\(=12:3=4\)

=4                         

`@` `\text {Ans}`

`\downarrow`

`a,`

`x - 280 \div 35 = 554`

`=> x - 8 = 554`

`=> x = 554 + 8`

`=> x = 562`

Vậy, `x = 562`

`b,`

`x + (5 \div 3) = 500`

`=> x + 5/3 = 500`

`=> x = 500 - 5/3`

`=> x = 1495/3`

Vậy, `x = 1495/3`

`c,`

`390 \div (5x - 5) = 39`

`=> 5x - 5 = 390 \div 39`

`=> 5x - 5 = 10`

`=> 5x = 10 + 5`

`=> 5x = 15`

`=> x = 15 \div 5`

`=> x = 3`

Vậy, `x = 3`

`d,`

`34x - 14x = 200`

`=> (34 - 14)x = 200`

`=> 20x = 200`

`=> x = 200 \div 20`

`=> x = 10`

Vậy, `x = 10.`

`@` `\text {Kaizuu lv uuu}`

a) \(x-280:35=554\)

\(x-8=554\)

\(x=562\)

b) \(x+\left(5:3\right)=500\)

\(x+\dfrac{5}{3}=500\)

\(x=500-\dfrac{5}{3}=\dfrac{1500}{3}-\dfrac{5}{3}=\dfrac{1495}{3}\)

c) \(390:\left(5x-5\right)=39\)

\(5x-5=\dfrac{39}{390}=\dfrac{1}{10}\)

\(5x=5+\dfrac{1}{10}\)

\(5x=\dfrac{51}{10}\)

\(x=\dfrac{51}{10}.\dfrac{1}{5}=\dfrac{51}{50}\)

d) \(34x-14x=200\)

\(20x=200\)

\(x=200:20=10\)

a: =250:{5*(78-28)}

=250:{5*50}

=1

b: \(=3\cdot\left\{150:\left[152-77\right]\right\}\)

=3*{150:75}

=3*2=6

c: \(=12:\left\{390:\left[500-125-245\right]\right\}\)

=12:3=4

d: =100-[16*5+88]:28

=100-6=94