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a, ( - 168 ) + 72 . ( - 168 ) + ( - 168 ) . 27
= ( - 168 ) + ( - 12096 ) + ( - 4536 )
= - 12264 + - 4536
= - 16800
b, 22 . ( - 3 ) - ( 110 + 8 ) : ( - 3 )2
= 4 . ( - 3 ) - ( 1 + 8 ) : 9
= ( - 12 ) - 9 : 9
= ( - 12 ) - 1
= - 13
c, ( - 1075 ) - ( 29 - 1075 )
= ( - 1075 ) - ( - 1046 )
= - 29
d, ( - 9 ) + ( - 11 ) + 21 + ( - 1 )
= - 20 + 21 + ( - 1 )
= 1 + - 1
= 0
e, 30 + 12 + ( - 20 ) + ( - 12 ) - ( 30 - 20 ) + ( 12 - 12 )
= 42 + ( - 20 ) + ( - 12 ) - 10 + 0
= 22 + ( - 12 ) - 10 + 0
= 10 - 10 + 0
= 0 + 0
= 0
g, ( 13 - 135 + 49 ) - ( 13 + 49 )
= [( - 122 ) + 49 ] - 62
= ( - 73 ) - 62
= - 135
h, 35 - { 12 - [ ( - 14 ) + ( - 2 ) } ]
= 35 - { 12 - ( - 16 ) }
= 35 - 28
= 7
Bài 2:
a. x - 35 = ( - 12 ) - 3
x - 35 = - 15
x = - 15 + 35
x = 20
b, \(\frac{1}{4}\)+ \(\frac{1}{3}\): 3x = - 5
\(\frac{3}{12}+\frac{4}{12}\): 3x = - 5
\(\frac{7}{12}\): 3x = - 5
3x = \(\frac{7}{12}\): - 5
3x = \(\frac{-7}{60}\)
x = \(\frac{-7}{60}\): 3
x = \(\frac{-7}{180}\)
c,2x-1 = 8
2x-1 = 24
x = 4 + 1
x = 5
a.17 . 85 + 25 . 17 + 1200
=17.(85+25)+1200
=17.110+1200
=1870+1200
=3070
b.62 : 4 . 3 + 2 . 52
=36:4.3+2.25
=27+50
=77
c.5 . 42 - 18 : 32
=5.16-18:9
=80-2
=78
d.3 . 52 - 16 : 23 + 34 : 33
=3.25-16:8+3
=75-2+3
=76
e.220 - [ 32 . 33 - ( 12 - 70 ) 2]
=220-35+112
=220-243+121
=98
j. 49 . 73 + 49 . 51 - 49 . 24
=49.(73+51-24)
=49.100
=4900
Con bấm mỏi suốt đấy mấy má
nhầm
a) 17 . 85 + 25 . 17 + 1200
=(17.85+25.17)+1200
=17(85+25)+1200
=17.110+1200
=1870+1200
=3070
b) 62 : 4 . 3 + 2 . 52
=36:4.3+2.25
=9.3+50
=27+50
=77
c) 5 . 42 - 18 : 32
=5.16-18:9
=80-2
=78
d) 3 . 52 - 16 : 23 + 34 : 33
=3.25-24:23+3(4-3)
=75-2(4-3)+31
=75-21+3
=75-2+3
=76
e) 220 - [ 32 . 33 - ( 12 - 70 ) 2 ]
=220-[3(2+3)-(12-1)2]
=220-(35-112)
=220-(243-121)
=220-122
=98
j) 49 . 73 + 49 . 51 - 49 . 24
=49(73+51-24)
=49.100
=4900
Đặt \(A=5+5^3+5^5+....+5^{47}+5^{49}\)
\(\Rightarrow5^2A=5^3+5^5+5^7+.....+5^{49}+5^{51}\)
\(\Rightarrow5^2A-A=\left(5^3+5^5+5^7+....+5^{49}+5^{51}\right)-\left(3+3^3+3^5+....+5^{47}+5^{49}\right)\)
\(\Rightarrow24A=5^{51}-5\)
\(\Rightarrow A=\dfrac{5^{51}-5}{24}\)
Vậy ............................................................
1)a) \(\left(3x-7\right)^5=32\Rightarrow\left(3x-7\right)^5=2^5\)
\(\Rightarrow3x-7=2\Rightarrow3x=9\Rightarrow x=3\)
Vậy \(x=3\)
b) \(\left(4x-1\right)^3=-27.125\)
\(\Rightarrow\left(4x-1\right)^3=-3^3.5^3=-15^3\)
\(\Rightarrow4x-1=-15\Rightarrow4x=-14\Rightarrow x=-3,5\)
Vậy \(x=-3,5\)
c) \(3^{4x+4}=81^{x+3}\Rightarrow3^{4x+4}=3^{4x+12}\)
\(\Rightarrow4x+4=4x+12\)
\(\Rightarrow4x=4x+8\)
\(\Rightarrow x\in\varnothing\)
d) \(\left(x-5\right)^7=\left(x-5\right)^9\)
\(\Rightarrow\left(x-5\right)^7-\left(x-5\right)^9=0\)
\(\Rightarrow\left(x-5\right)^7.\left[1-\left(x-5\right)^2\right]=0\)
\(\Rightarrow\left[{}\begin{matrix}\left(x-5\right)^7=0\\1-\left(x-5\right)^2=0\end{matrix}\right.\Rightarrow\left[{}\begin{matrix}x=5\\\left(x-5\right)^2=1\end{matrix}\right.\)
\(\Rightarrow\left[{}\begin{matrix}x=5\\x-5=-1\\x-5=1\end{matrix}\right.\Rightarrow\left[{}\begin{matrix}x=5\\x=4\\x=6\end{matrix}\right.\)
Vậy \(\left[{}\begin{matrix}x=5\\x=4\\x=6\end{matrix}\right.\)
a, 53 * 39 + 47 * 59 - 53 * 21 - 47 * 21 c, (43 * 52 - 43 ) : ( 4 * 42 )
= ( 53 + 47 ) * 39 - ( 53 + 47 ) * 21 = ( 64 * 25 - 64 ) : ( 4 * 16 )
= 100 * 39 - 100 * 21 = ( 1600 - 64 ) : 64
= ( 39 - 21 ) * 100 = 1536 : 64
= 18 * 100 = 24
= 1800
a) 49.(-34)+(-65).49-49 = 49. (-34-65-1)= 49. (-100)= -4900
b) -268-(-47-168)-147 = (-268 + 168) - (147 - 47)= -100 -100=-200
c) (-2)2.(-3)-[(-1)2024+8]:(-3)2 = 4. (-3) - [1 +8]:9 = -12 - 9:9 = -12 - 1 = -13
d) 67-[8+7.32 -24:6+(9-7)3]:15 = 67 - [8 + 7.9 - 4 + 23 ] : 15
= 67 - [8+63-4+8]:15 = 67 - 75:15 = 67 - 5 = 62