(1259 - 3y) : 5 = 55

=> 1259 - 3y = 275

=> 3y = 984

=> y = 328

( 1259 - y x 3 ) : 5 = 55

1259 - y x 3 = 55 x 5

1259 - y x 3 = 275

           y x 3 = 1259 - 275

           y x 3 = 984

                y = 984 : 3

                y = 328

1259 - y x 3 = 55 x 5 = 275

y x 3 = 1259 - 275 = 984

y = 984 : 3 

y = 328

=> 1259 - 3x = 275

=> 3x = 984

=> x = 328

(1259-3x):5=55

1259-3x=275

3x=1259-275

3x=984

x=328

\(a.\left(35-815\right)-\left(795-65\right)\\ =35-815-795+65\\ =\left(35+65\right)-\left(815+795\right)\\ =100-1610=-1510\)

Bài 2: 

a: Ta có: \(\left(35-815\right)-\left(795-65\right)\)

\(=35-815-795+65\)

\(=100-1600\)

=-1500

b: Ta có: \(5-197-2015-2015\)

\(=-2010-2212\)

=-4222

c: Ta có: \(1259-1409-12+1259+1409\)

\(=2518-12\)

=2506

tôi ko bt làm như nào mọi người thông cảm

( x + 1259 ) x 5 = 67845

( x + 1259 )      = 67845 : 5

( x + 1259 )      = 13569

x                       = 13569 - 1259

x                       = 12310

Mình nghĩ đề bài sai bạn ạ

tk nhé

ai k mình mình k lại

(x+1259)x5=12345+45691

(x+1259)x5=58036

x+1259      =58036:5

x+1259      =11607,2

               x=11607,2-1259

               x=10348,2

25¹²=(5²)¹²=5^2.12=5²⁴

125⁹=(5³)⁹=5^3.9=5²⁷

ta có 5²⁷>5²⁴

=>125⁹>25¹²

25¹² < 125⁹

Ta có :
\(25^{12}=\left(5^2\right)^{12}=5^{24}\)
\(125^9=\left(5^3\right)^9=5^{27}\)
=> 25^12 < 125^9
~ HT ~

1259 + x = 3457

x = 3457 - 1259

x = 2198   

x=3457-1259

x=2198

3457 -1259 = 2198

bài 1

a)-7105-(155-7105)+355
 =-7105 -155 +7105 +355
 =(-7105 + 7105)+(-155 + 355)

 =0 + 200

=200
 

b)(35−815)−(795−65)b)(35-815)-(795-65)

=−780−730=-780-730

=−1510

$a\left)\right(-7105)-(155-7105)+355$

$=(-7105)-155+7105+335$

$=\left[\right(-7105)+7105]+(355-155)$

$=0+200$

$=200$

$b\left)\right(35-815)-(795-65)$

$=35-815-795+65$

$=(35+65)+\left[\right(-815)-795]$

$=100+(-1610)$

$=-1510$

c)5−197−2015−2015c)5−197−2015−2015

=(5−197)+[(−2015)−2015]=(5−197)+[(−2015)−2015]

=(−192)+(−4330)=(−192)+(−4330)

=−4522=−4522

d)4567+1234−4567−(−66)d)4567+1234−4567−(−66)

=(4567−4567)+[1234−(−66)]=(4567−4567)+[1234−(−66)]

=0+1300=0+1300

=1300
 

e)2004−15+54−2004−54e)2004−15+54−2004−54

=(2004−2004)+(54−54)−15=(2004−2004)+(54−54)−15

=0+0−15=0+0−15

=−15
 

g)1259−1409−12+1259+1409g)1259−1409−12+1259+1409

=(1259+1259)+(1409−1409)−12=(1259+1259)+(1409−1409)−12

=2518+0−12=2518+0−12

=2506