Hãy nhập câu hỏi của bạn vào đây, nếu là tài khoản VIP, bạn sẽ được ưu tiên trả lời.
a)5.(-8).2.(-3)
=[5.(-2)].[(-8).(-3)]
=-10.24
=-240
b)(45-135+72)-(45+72)
=45-135+72-45-72
=(45-45)+(72-72)-135
=0+0-135
=-135
c)3.(-5)2.2+2.(-5)-20
=3.25.2+2(-5)-20
=75.2+(-10)-20
=150+(-30)
=120
d)86.(-46)+46.27-46.41
=86.(-1).46+46.27-46.41
=-86.46+46.27-46.41
=46(-86+27-41)
=46(-100)
-4600
e)34(15-10)-15(34-10)
=34.15-34.10-15.34+15.10
=(34.15-15.34)+(15.10-34.10)
=[34(15-15)]+[10(15-34)]
=34.0+10(-9)
=0+(-90)
=-90
1/Ta co :
\(\dfrac{15}{7}.\left(\dfrac{1}{5}-\dfrac{46}{45}\right)+\dfrac{46}{45}.\left(\dfrac{15}{7}-\dfrac{45}{46}\right)\)
=\(\dfrac{15}{7}.\dfrac{1}{5}-\dfrac{15}{7}.\dfrac{46}{45}+\dfrac{46}{45}.\dfrac{15}{7}-\dfrac{46}{45}.\dfrac{45}{46}\)
=\(\dfrac{15}{7}.\left(\dfrac{1}{5}-\dfrac{46}{45}+\dfrac{46}{45}\right)-1\)
=\(\dfrac{15}{7}.\dfrac{1}{5}-1\)
=\(\dfrac{3}{7}-1=\dfrac{-4}{7}\)
2/Ta co
\(\dfrac{43}{47}.\left(\dfrac{18}{37}+\dfrac{47}{43}\right)-\dfrac{18}{3}.\left(\dfrac{43}{47}+\dfrac{37}{36}\right)\)
=\(\dfrac{43}{47}.\dfrac{18}{37}+\dfrac{43}{47}.\dfrac{47}{43}-\dfrac{18}{37}.\dfrac{43}{47}+\dfrac{18}{37}.\dfrac{37}{36}\)
=\(\dfrac{18}{37}.\left(\dfrac{43}{37}-\dfrac{43}{37}+\dfrac{37}{36}\right)+1\)
=\(\dfrac{18}{37}.\dfrac{37}{36}+1\)
=\(\dfrac{1}{2}+1=\dfrac{3}{2}\)
tick cho mk nha
a ) 48 - 73 + |15| - ( - 29 )
= -25 + 15 + 29 = 19
b) 134 + 46.( 39 - 78 ) - | 267 |
= 134 + 46.( -39 ) - 267 = -133 -1794 = -1927
c) 36 - 16.( -2 )² + ( - 53 )
= 36 - 16.4 - 53 = -17 - 64 = -81
d) ( 259 - 47 - 5 ) - ( 259 - 5 )
= 259 - 47 - 5 - 259 + 5 = - 5 + 5 + 259 - 259 = 0
e ) 325. 26 - 325 . 125 - 325
= 325 (26 - 125 - 1) = 325. (-100) = -32500
1-2+3-4+5-6+............+45-46+47-48+100
= (1-2)+(3-4)+(5-6)+............+(45-46)+(47-48)+100
= (-1) + (-1) + (-1)+ ...............+(-1)+(-1) +100 ( có 24 cặp -1)
=(-1)x24+100
=( -24) +100
=76
Nhớ k cho mk nha! ^-^
45-58+(-45)+(+58)-3=45-58-45+58-3=(45-45)+(58-58)-3=-3
(-57)-(-12)+3-(-57)=-57+12+3+57=(-57+57)+12+3=15
-(-24)-(-30)+(-24)-30+8=24+30-24-30+8=(24-24)+(30-30)+8=8
-(-12)+(+19)-(+12)+8-19=12+19-12+8-19=(12-12)+(19-19)+8=8
47-(-53)+(-47)-(+53)=47+53-47-53=(47-47)+(53-53)=0
-(+28)+32-(-28)+(-34)=-28+32+28-34=(-28+28)-(34-32)=-2
15-(+72)+(-15)+(+72)=15-72-15+72=(15-15)+(72-72)=0
20-(+46)+(-25)-(-46)=20-46-25+46=(20-25)+(46-46)=-5
28-(-32)+(-28)-32+5=28+32-28-32+5=(28-28)+(32-32)+5=5
-75+(-49)+(+75)+49-12=-75-49+75+49-12=(-75+75)+(49-49)-12=-12
\(...=45-58-45+58-3=-3\)
\(...=-57+12+3+57=15\)
\(...=24+30-24-30+8=8\)
\(...=12+19-12+8-19=8\)
\(...=47+53-47-53=0\)
\(...=-28+32+28-34=-2\)
\(...=15-72-15+72=0\)
\(...=20-46-25+46=-5\)
\(=...28+32-28-32+5=5\)
\(...=-75-49+75+49-12=-12\)
\(\left[\left(46-32\right)^2-\left(54-42\right)^2\right]\times36-1872\)
\(=\left(14^2-12^2\right)\times36-1872\)
\(=\left(196-144\right)\times36-1872\)
\(=52\times36-1872\)
\(=1872-1872\)
\(=0\)
5+10+15+......+205=4305
47-46+46-45+.......+2-1=46
K nhé mn?
5 + 10 + 15 + ... + 205
Ta có :
Khoãng cách giữa hai số liên tiếp là 5 đơn vị .
Số số hạng của dãy là : (205 - 5) : 5 + 1 = 41 ( số hangk)
Tổng của dãy là : (205 + 5) x 41 : 2 = 4305
Vậy 5 + 10 + 15 + 205 = 4305