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$\textbf{a)}$
$\{[126-(36-31)^2\cdot2]-9\}\cdot1001$
$=\{126-5^2\cdot2-9\}\cdot1001$
$=(126-50-9)\cdot1001$
$=67\cdot1001$
$=67067.$
$\textbf{b)}$
$\{315-[(60-41)^2-361]\cdot4217\}+2885$
$=\{315-(19^2-361)\cdot4217\}+2885$
$=\{315-(361-361)\cdot4217\}+2885$
$=315+2885$
$=3200.$
$\textbf{a)}$
$\{[261-(36-3)\cdot3^2]-9\}\cdot1001$
$=\{261-33\cdot9-9\}\cdot1001$
$=(261-297-9)\cdot1001$
$=-45\cdot1001$
$=-45045.$
$\textbf{b)}$
$\{315-[(660-41)^2-361]\cdot4217\}+2885$
$=\{315-(619^2-19^2)\cdot4217\}+2885$
$=\{315-(619-19)(619+19)\cdot4217\}+2885$
$=\{315-600\cdot638\cdot4217\}+2885$
$=3200-1613691600$
$=-1613688400.$
$\textbf{A}$
$A=[261-(36-31)^3\cdot2]-9\cdot1001$
$=[261-5^3\cdot2]-9009$
$=[261-125\cdot2]-9009$
$=(261-250)-9009$
$=11-9009$
$=-8998.$
$\textbf{B}$
$B=\{315-[(60-41)^2-361]\cdot4217\}+2885$
$=\{315-(19^2-361)\cdot4217\}+2885$
$=\{315-(361-361)\cdot4217\}+2885$
$=315-0+2885$
$=3200.$
bài 1
a)
=> 3(x-2)=60-51
=> 3(x-2) =9
=> x-2 =9:3
=> x-2 =3
=> x =3+2
=> x =5
b)
=>4x-20=25-2
=>4x-20=23
=>4x-20=8
=>4x=8+20
=>4x=28
=>x=28:4
=>x=7
c)
=> 25+x.5-64=251
=> x.5-64 =251-25
=> x.5-64 =226
=> x.5 =226+64
=> x.5 =290
=> x =290:5
=> x =58
d)
=> [(14)2 - (12)2].2x=1872
=> 52.2x =1872
=> 104x =1872
=> x = 1872:104
=> x=18
e)
x10=x
=> x10-x=0
=>x(x9-1)=0
=>\(\orbr{\begin{cases}x=0\\x^9-1=0\end{cases}\Rightarrow\orbr{\begin{cases}x=0\\x^9=1\Rightarrow x=1\end{cases}}}\)
nha
mình sẽ làm típ
T I C K cho mình mình sẽ làm típ
Bài 1
\(131\times x-341=1024\)
\(131\times x=1024+341=1365\)
\(x=1365\div131\)
\(\Rightarrow x=\frac{1365}{131}\)
Bài 2
B=\(\frac{\left(498-2\right)\div2+1}{2}\times\left(498+2\right)\)
B=\(62250\)
Bài 1: Thực hiện phép tính
a) 165 - [ 120 - ( 9 - 4 )2 ]
b) 32 : { 160 : [ 300 - ( 175 + 21 . 5 ) ] }
c) 6 . 52 - 32 : 24 + 32
d) 42 .37 - 42 . 33 + 24
Bài làm:
a) 165 - [ 120 - ( 9 - 4 )2 ]
= 165 - [ 120 - 52 ]
= 165 - [ 120 - 25 ]
= 165 - 95
= 70.
b) 32 : { 160 : [ 300 - ( 175 + 21 . 5 ) ] }
= 32 : { 160 : [ 300 - ( 175 + 105) ] }
= 32 : { 160 : [ 300 - 280 ] }
= 32 : { 160 : 20 }
= 32 : 8
= 4.
c) 6 . 52 - 32 : 24 + 32
= 6 . 25 - 32 : 16 + 9
= 150 - 2 + 9
= 148 + 9
= 157.
d) 42 .37 - 42 . 33 + 24
= 16. ( 37 - 33)
= 16 . 4
= 64.
Bài 2: Tìm số tự nhiên x, biết:
a) 91-5 . ( 5 + x ) = 61
b) ( x + 34 ) - 40 = 28
c) 3 . ( x -2 ) + 150 = 240
d) 360 : ( x- 7) = 90
e) 2448 : [ 119 - ( x - 6) ] = 24.
Bài làm:
a) 91-5 . ( 5 + x ) = 61
5 . ( 5 + x) = 91 - 61
5. ( 5+ x) = 30
5 +x = 30 : 5
5 +x = 6
x = 6 - 5
x = 1.
b) ( x + 34 ) - 40 = 28
x+ 34 = 40 + 28
x+ 34 = 68
x = 68 - 34
x = 34.
c) 3 . ( x - 2 ) + 150 = 240
3 . ( x - 2 ) = 240 - 150
3 . ( x - 2 ) = 90
x - 2 = 90 : 3
x - 2 = 30
x = 30 + 2
x = 32.
d) 360 : ( x - 7 ) = 90
x - 7 = 360 : 90
x - 7 = 4
x = 4 + 7
x = 11.
e) 2448 : [ 119 - ( x - 6 ) ] = 24
[ 119 - ( x - 6 ) ] = 2448 : 24
[ 119 - ( x - 6 ) ] = 102
x - 6 = 119 + 102
x - 6 = 221
x = 221 + 6
x = 227.
********************************Chúc bạn học tốt***********************************
$\textbf{Bài 1a}$
$\{[216-(36-31)^3\cdot2]-9\}\cdot1001$
$=\{216-5^3\cdot2-9\}\cdot1001$
$=(216-250-9)\cdot1001$
$=(-43)\cdot1001$
$=-43043.$
$\textbf{Bài 1b}$
$\{315-[(60-41)^2-361]\cdot4217\}+2885$
$=\{315-(19^2-361)\cdot4217\}+2885$
$=\{315-(361-361)\cdot4217\}+2885$
$=315+2885$
$=3200.$
$\textbf{Bài 1c}$
$[(46-32)^2-(54-42)^2]\cdot36-1872$
$=(14^2-12^2)\cdot36-1872$
$=(14-12)(14+12)\cdot36-1872$
$=2\cdot26\cdot36-1872$
$=52\cdot36-1872$
$=1872-1872$
$=0.$
$\textbf{Bài 2a}$
$[(x+32)-17]\cdot2=42$
$\Leftrightarrow(x+15)\cdot2=42$
$\Leftrightarrow x+15=21$
$\Leftrightarrow x=6.$
$\textbf{Bài 2b}$
$131x-341=27\cdot23$
$\Leftrightarrow131x-341=621$
$\Leftrightarrow131x=962$
$\Leftrightarrow x=\dfrac{962}{131}.$
$\textbf{Bài 3a}$
$A=1+2+3+\cdots+300$
$=\dfrac{(1+300)\cdot300}{2}$
$=301\cdot150$
$=45150.$
$\textbf{Bài 3b}$
$B=2+4+6+\cdots+498$
$=2(1+2+3+\cdots+249)$
$=2\cdot\dfrac{(1+249)\cdot249}{2}$
$=250\cdot249$
$=62250.$