=-45*312-312+312*(-54)

=312(-45-1-54)

=-31200

( - 45 ) . 312 - 312 - ( - 54 ) . ( - 312 )

= 312 . ( - 45 - 54 - 1 )

= 312 . ( - 100 )

= - 31 200

:D lỗi rồi

a) $420-(71+420)$

$=420-71-420$

$=-71$

b) $(35-120)+(120+410-35)$

$=35-120+120+410-35$

$=(35-35)+(-120+120)+410$

$=410$

c) $(320-15+49)-(85-51)$

$=320-15+49-85+51$

$=320+(-15-85)+(49+51)$

$=320+(-100)+100$

$=320$

d) $-(312+59)-(41+400+88)$

$=-312-59-41-400-88$

$=(-312-88)+(-59-41)-400$

$=-400+(-100)-400$

$=-500-400$

$=-900$

e) $(430-731)-(-731+430-56)$

$=430-731+731-430+56$

$=(430-430)+(-731+731)+56$

$=56$

f) $(1352-47)-(53-1000+1352)$

$=1352-47-53+1000-1352$

$=(1352-1352)+(-47-53)+1000$

$=(-100)+1000$

$=1000-100$

$=900$

h) $(-42)-(370+58)-(120-370)$

$=-42-370-58-120+370$

$=(-42-58)+(-370+370)-120$

$=-100-120$

$=-220$

$Toru$

Chịu

a)(-45).312-312-54.312

=312.[(-45)-1-54]

=312.(-100)

=-31200

b)217.(-46)-217.15-217.40+27

=217.[(-46)-15-40]+27

=217.(-101)+27

=217.[(-100)+(-1)]+27

=-21700+(-217)+27

=-21700+(-190)

=-21890

-43.15+43.48-48.43+48.15

=(-43.15+48.15)-(43.48-48.43)

=5.15-0=75

a: a chia hết cho 3 vì 27 chia hết cho 3;81 chia hết cho 3 và 243 chia hết 3

b:B chia hết cho 5 vì 225 chia hết cho 5 và 110 chia hết cho 5

c: Các số chia hết cho cả 2,3,5 là 450

`@` `\text {Ans}`

`\downarrow`

`a)`

`2 \times x + 34 = 168`

`=> 2x = 168 - 34`

`=> 2x = 134`

`=> x = 134 \div 2`

`=> x = 67`

Vậy, `x=67`

`b)`

`x \times 11 + 51 = 273`

`=> 11x = 273 - 51`

`=> 11x = 222`

`=> x = 222 \div 11`

`=> x = 222/11`

`c)`

`x \div 120 - 45 = 155`

`=> x \div 120 = 155 + 45`

`=> x \div 120 = 200`

`=> x = 200 \times 120`

`=> x = 24000`

Vậy, `x = 24000`

`d)`

`320 \div x - 127 = 33`

`=> 320 \div x = 33+127`

`=> 320 \div x = 160`

`=> x = 320 \div 160`

`=> x = 2`

Vậy, `x=2.`

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

a)2 x x +34 =168

2 x X = 168 - 34

2 x X = 134

X= 134:2

X= 67

b) x x 11 + 51 = 273

X x 11 = 273 - 51

X x 11= 222

X= 222 :11

X= 222/11

c) x : 120 – 45 = 155

x:120= 155+45

x:120=200

x=200:120

x=5/3

d) 320 : x – 127 = 33

320: x= 33+127

320:x=160

x=320:160

x=2

2 . x + x : 3 . 4,5 + x : 10 . 45 = 320

2 . x + x . 1/3 . 4,5 + x . 1/10 . 45 = 320

x . ( 2 + 1/3 . 4,5 + 1/10 . 45 ) = 320

x . ( 2 + 1,5 + 4,5 ) = 320

x . 8 = 320

     x = 320 : 8

     x = 40

bang 40 nha!