\(a,31.\left(-18\right)+31.\left(-81\right)-31\)

\(=31\left(-18-81-1\right)\)

\(=31\left(-100\right)\)

\(=-3100\)

\(b,13\left(23+22\right)-3\left(17+28\right)\)

\(=299+286-51-84\)

\(=450\)

Cảm ơn

a) 13.(23+22)-3.(17+28)

= 13.45 - 3.45

= 45(13-3)

= 45.10 =450

b) -48+48.(-78)+48(-21)

= -48 + 48(-78 - 21)

= -48 + 48.(-99)

= -48 + ( -4752)

= -4800

c) 135.(171-123)-171.(135-123)

= 135.171 - 135.123 - 171.135 + 171.123

= (135.171 - 171.135) - (135.123 - 171.123)

= - 123(135 - 171) = (-123).(-36)= 4428

d: =(1-2)+(3-4)+...+(99-100)

=(-1)+(-1)+...+(-1)

=-50

j: SỬa đề: -1+3-5+7-...-97+99

=(-1+3)+(-5+7)+...+(-97+99)

=2+2+...+2

=2*50=100

e: Sửa đề: 2-4+6-8+...+46-48+50

=(2-4)+(6-8)+...+(46-48)+50

=50-2*24=50-48=2

nhiều quá à

nhìn mk ko muốn làm

nhiều bài quá

chúc bn học gioi!

ahjhj

1> 31.(-18)+31.(-81)-31

=31(-18-81-1)

=31.-100

=-3100

jup mk vs ạ

đg cần gấp!

jup đi mak 

ai bt lm hộ cái zùi trả công cho!!!!!!!1

31.(-18)+31.(-81)-31

= 31.[(-18)+(-81)]

= 31.(-100)

= -3100

135.(171-123)-171.(135-123)

=(135.171-135.123)-(171.135-171.123)

=135.171-135.123-171.135+171.123

=(135.171-171.135)-(135.123-171.123)

=0-123.(135-171)

=0-(-4428)=4428

K)-(-2009+97)-74.(-18)+74.(-118)-2009-3

=2009-97-74.(-18)+74.(-118)-2009-3

=2009-97-74.[(-18)+118]-2009-3

=(2009-2009)-74.100-(97+3)

=0-7400-100

=-7400-100=-7500

Mik bổ sung thêm nha

35.18-5.7.28

= 35.18-35.28

= 35.(28-18)

= 35.10

= 350

Câu 1:

a) Ta có: 2n+1 là số lẻ∀n

⇒\(\left(-1\right)^{2n+1}=-1\)

Ta có: \(\left(-25\right)\cdot21\cdot\left(-2\right)^2\cdot\left(-\left|-3\right|\right)\cdot\left(-1\right)^{2n+1}\)

\(=-25\cdot21\cdot4\cdot\left(-3\right)\cdot\left(-1\right)\)

\(=75\cdot84\cdot\left(-1\right)\)

\(=-6300\)

b) Ta có: \(\left(-5\right)^3\cdot67\cdot\left(-\left|-2^3\right|\right)\cdot\left(-1\right)^{2n}\)

\(=-125\cdot67\cdot\left(-8\right)\)

\(=1000\cdot67=67000\)

c) Ta có: \(35\cdot18-5\cdot7\cdot28\)

\(=35\cdot18-35\cdot28\)

\(=35\cdot\left(18-28\right)=35\cdot\left(-10\right)=-350\)

d) Ta có: \(24\cdot\left(16-5\right)-16\cdot\left(24-5\right)\)

\(=24\cdot16-24\cdot5-24\cdot16+16\cdot5\)

\(=-24\cdot5+16\cdot5\)

\(=5\cdot\left(-24+16\right)=5\cdot\left(-8\right)=-40\)

e) Ta có: \(29\cdot\left(19-13\right)-19\cdot\left(19-13\right)\)

\(=6\cdot\left(29-19\right)=6\cdot10=60\)

g)Sửa đề: \(31\cdot\left(-18\right)+31\cdot\left(-81\right)-31\)

Ta có: \(31\cdot\left(-18\right)+31\cdot\left(-81\right)-31\)

\(=31\cdot\left(-18-81-1\right)\)

\(=31\cdot\left(-100\right)=-3100\)

h) Ta có: \(\left(-12\right)\cdot47+\left(-12\right)\cdot52+\left(-12\right)\)

\(=-12\cdot\left(47+52+1\right)\)

\(=-12\cdot100=-1200\)

k) Ta có: \(13\cdot\left(23+22\right)-3\cdot\left(17+28\right)\)

\(=13\cdot45-3\cdot45\)

\(=45\cdot\left(13-3\right)=45\cdot10=450\)

m) Ta có: \(-48+48\cdot\left(-78\right)+48\cdot\left(-21\right)\)

\(=48\cdot\left(-1-78-21\right)\)

\(=48\cdot\left(-100\right)=-4800\)

n) Ta có: \(135\cdot\left(171-123\right)-171\cdot\left(135-123\right)\)

\(=135\cdot171-135\cdot123-171\cdot135+171\cdot123\)

\(=123\cdot\left(-135+171\right)=123\cdot36=4428\)