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1)17-2(2x-3)=3
2(2x-3)=17-3
2(2x-3)=14
2x-3 =14:2
2x-3 =7
2x =7+3
2x =10
x =10:2
x =5
1) 17 - 2(2x - 3) = 3
=> 17 - 4x + 6 = 3
=> 23 - 4x = 3
=> 4x = 23 - 3
=> 4x = 20
=> x = 20 : 4 = 5
2) 125 - 5(3x - 1) = 25
=> 125 - 15x + 5 = 25
=> 130 - 15x = 25
=> 15x = 130 - 25
=> 15x = 105
=> x = 105 : 15
=> x = 7
3) 70 - 5(2x - 3) = 45
=> 70 - 10x + 15 = 45
=> 85 - 10x = 45
=> 10x = 85 - 45
=> 10x = 40
=> x = 40 : 10
=> x = 4
4) 231 - (x - 6) = 133 : 13
=> 231 - x + 6 = 133/13
=> 237 - x = 133/13
=> x = 237 - 133/13
=> x = 2948/13
a) Xem lại đề.
b) 5. (x - 3)2 + 17 = 142
5. (x - 3)2 = 142 - 17
5. (x - 3)2 = 125
(x - 3)2 = 125 : 5
(x - 3)2 = 25
(x - 3)2 = 52 (cùng số mũ)
⇒ x - 3 = 5
x = 5 + 3 = 8
c) [(6x - 72) : 2 - 84] . 28 = 5628
[(6x - 72) : 2 - 84] = 5628 : 28
[(6x - 72) : 2 - 84] = 201
(6x - 72) : 2 = 201 + 84
(6x - 72) : 2 = 285
6x - 72 = 285. 2
6x - 72 = 570
6x = 570 + 72
6x = 642
x = 642 : 6
x = 107
123-5.(x+4)=38
5.(x+4)=123-38
5.(x+4)=85
x+4=85:5
x+4=17
x=17-4
x=13
(3.x-2^4).7^3=2.7^4
(3.x-16).343=2.2401
(3.x-16).343=4802
3.x-16=4802:343
3.x-16=14
3.x=14+16
3.x=30
x=30:3
x=10
6^2:4.3+2.5^2
=36:4.3+2.25
=9.3+2.25
=27+50
=77
5.4^2-18:3^2
=5.16-18:9
=80-2
=78
80-(4.5^2-3.2^3)
=80-(4.25-3.8)
=80-(100-24)
=80-76
=4
23.75+25.23+180
=23.(75+25)+180
=23.100+180
=2300+180
=2480
2448:[119-(23-6)]
=2448:(119-17)
=2448:102
=24
(2600+6400)-3.x=1200
9000-3.x=1200
3.x=9000-1200
3.x=7800
x=7800:3
x=2600
[(6.x-72):2-84].28=562
(6.x-72):2-84=562:28
(6.x-72):2-84=281/14
(6.x-72):2=281/14+84
(6.x-72):2=1457/14
6.x-72=1457/14.2
6.x-72=1457/7
6.x=1457/7+72
6.x=1961/7
x=1961/7:6
x=1961/42
A.35 x 34 + 35 x 38 + 65 x 75 + 65 x 45
Câu này không tính hợp lí được
B. 12x 53 + 53 x 172 - 53 x 84
= 53 x (12 + 172 - 84)
= 53 x 100
= 5300
C. 36 x 28 + 36 x 82 + 64 x 69 + 64 x 41
= 36 x (28+82) + 64 x (69+41)
= 36 x 110 + 64 x 110
= (36+64) x 110
= 100 x 110
= 11 000
D. A = 1+2+3+...+100
= (1+ 100) x 50
= 101 x 50
= 5050
E. B =17+19+...+101+103
= (103 +17) x [(103 - 17):2 + 1]
= 120 x 44
=5280
G. D= 3x (12+13+14+15) + 3x(8+7+6+5)
= 3 x (5+6+7+8+12+13+14+15)
= 3 x (20 x 4)
= 3 x 80
=240
a) \(128-3\left(x+4\right)=23\)
\(\Rightarrow3\left(x+4\right)=128-23\)
\(\Rightarrow3\left(x+4\right)=105\)
\(\Rightarrow x+4=105:3\)
\(\Rightarrow x+4=35\)
\(\Rightarrow x=35-4\)
\(\Rightarrow x=31\)
Vậy x = 31
b) \(\left(6x-3^3\right).5^3=3.5^4\)
\(\Rightarrow6x-27=3.5^4:5^3\)
\(\Rightarrow6x-27=15\)
\(\Rightarrow6x=15+27\)
\(\Rightarrow6x=42\)
\(\Rightarrow x=42:6\)
\(\Rightarrow x=7\)
Vậy x = 7
c) \(2448:\left[119-\left(x-6\right)\right]=24\)
\(\Rightarrow119-\left(x-6\right)=2448:24=102\)
\(\Rightarrow x-6=119-102=17\)
\(\Rightarrow x=17+6=23\)
Vậy x = 23
d) \(130-\left[5.\left(9-x\right)+43\right]=47\)
\(\Rightarrow5.\left(9-x\right)+43=130-47=83\)
\(\Rightarrow5.\left(9-x\right)=83-43=40\)
\(\Rightarrow9-x=40:5=8\)
\(\Rightarrow x=9-8=1\)
Vậy x = 1
128 - 3( x+4 ) = 23
=> 3 (x+4) = 128 -23
=> 3(x+4) = 105
=> x+4 = 105 / 3
=> x+4 = 35
=> x = 35 - 4
=> x = 31
Vậy x = 31
Mình không chép lại đề nha
a)119-(x-6)=102
x-6 =17
x =23
b)(6x-39):7=3
6x-39 =21
6x =60
x =10
c, d bạn tự làm nha
a)73+86+968+914+3032
= (86 + 914) +(968 + 3032) + 73
= 1000 + 4000 + 73
= 5073
b)341.67+341.16+659.83
=341 (67 + 16) + 659 * 83
= 341 * 83 + 659 * 83
= (341+ 659) * 83
= 1000 * 83
= 830000
c)252-84:21+7
= 252 - 2 +7
=257
d)4.8.25.125.27
= (8 * 125) (4* 25) * 27
= 1000 * 100 * 27
= 2700000
e)34+35+36+37-24-25-26-27
= (34-24) + (35-25) + (36-26) + (37-27)
= 10 + 10 + 10 + 10
= 40
g)1-2+3-4+...-98+99
= (1 + 99) + (-2-98) + .....+ (-48 - 52) + (49 + 51) - 50
= 100 - 50
= 50
h)1-4+7-10+...-100+103
Bài 2:Tìm số nguyên x,biết:
l)3636:(12.x-91)=36
3636 : (12x - 91) = 36
12x - 91 = 101
12x = 192
x= 16
m)(x:23+45).67=8911
x: 23 + 45 = 133
x : 23 = 88
x= 88/23
n)[(6.x-39):7].4=12
6x - 39 = 3
6x = 42
x=7
p)128-3(x+4)=23
3(x+4) = 105
x+4= 35
x= 31
q)[(4.x+28).3+55]:5=35
(4x + 28)*3 +55 = 175
(4x + 28) * 3 = 120
4x + 28 = 40
4x = 12
x=3
r)123-5.(x+4)=38
5(x+4) = 85
x+4 = 17
x= 13
t)11-(53+x)=97
53 + x = -86
x= -139
i)23.75+25.23+180
= 23(75+25) + 180
= 2300 + 180
= 2480