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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
1) 3x = 45 + 15 = 60
x = 60 : 3 = 20
2) 5x = 50 - 35 = 15
x = 15 : 5 = 3
3) (2x - 5) + 17 = 6
2x - 5 = 6 - 17
2x - 5 = -11
2x = -11 + 5
2x = -6
x = -6 : 2 = -3
4) 10 - 2(4 -3x) = -4
2(4 - 3x) = -4 - 10 = -14
4 - 3x = -14 : 2 = -7
3x = -7 - 4 = -18
x = -18 : 3 = -6
\(\left\{{}\begin{matrix}\left\{{}\begin{matrix}3x-15=45\Leftrightarrow3x=60\Leftrightarrow x=20\\35-5x=50\Leftrightarrow5x=-15\Leftrightarrow x=-3\end{matrix}\right.\\\left\{{}\begin{matrix}\left(2x-5\right)+17=6\Leftrightarrow2x+5=-11\Leftrightarrow2x=-16\Leftrightarrow x=-8\\10-2\left(4-3x\right)=-4\Leftrightarrow8-6x=14\Leftrightarrow6x=-6\Leftrightarrow x=-1\end{matrix}\right.\\\left\{{}\begin{matrix}-12+3\left(-x+7\right)=-18\Leftrightarrow-3x+21=-6\Leftrightarrow-3x=-27\Leftrightarrow x=9\\24:\left(3x-2\right)=-3\Leftrightarrow3x-2=-8\Leftrightarrow3x=-6\Leftrightarrow x=-2\end{matrix}\right.\\-45:5\left(-3-2x\right)=3\Leftrightarrow-15-10x=-15\Leftrightarrow10x=0\Leftrightarrow x=0\end{matrix}\right.\)
a) 70 - 5 ( 2x-3 ) = 45
5( 2x-3 ) = 25
2x - 3 = 25 : 5
2x - 3 = 5
2x = 8
x = 8 : 2
x = 4
b) 6 ( 5x + 35 ) = 330
5x + 35 = 330 : 6
5x + 35 = 55
5x = 55 - 35
5x = 20
x = 20 : 5
x = 4
c) 936 - ( 4x + 24 ) = 72
4x + 24 = 936 - 72
4x + 24 = 864
4x = 864 - 24
4x = 840
x = 840 : 4
x = 210
d) 5( 3x + 34 ) = 515
3x + 34 = 515 : 5
3x + 34 = 103
3x = 103 - 34
3x = 69
x = 69 : 3
x = 23
\(a,70-5\left(2x-3\right)=45\)
\(\Leftrightarrow10x-15=70-45\)
\(\Leftrightarrow10x=25+15\)
\(\Leftrightarrow x=\frac{40}{10}=4\)
Vậy x=4
\(b,6\left(5x+35\right)=330\)
\(\Leftrightarrow5x+35=55\)
\(\Leftrightarrow5x=20\)
\(\Leftrightarrow x=4\)
vậy x=4
\(c,936-\left(4x+24\right)=72\)
\(\Leftrightarrow4x+24=936-72\)
\(\Leftrightarrow4x=864-24\)
\(\Leftrightarrow x=840:4=210\)
Vậy x=210
\(d,5\left(3x+34\right)=515\)
\(\Leftrightarrow3x+34=515:5\)
\(\Leftrightarrow3x=103-34\)
\(\Leftrightarrow x=69:3=23\)
Vậy x=23
a.70 -5.(x-3)=45
x-3=70-5-45
x-3=20
x=20-3=17
b.2x-138=8.9
2x-138=72
2x=72+138
2x=210
x=210:2=105
c.10+2n=16
2n=16-10
2n=6
n=6:3=2
d.[(4x+28).3+55]:5=35
[(4x+28).3+55]=35x5=175
4x+28=(175-55):3
4x+28=40
4x=40-28=12
x=12:4=3
Dung thi k mk nha
Chuc bn hoc gioi nha
\(6^2-\left(x+3\right)=45\)
\(36-\left(x+3\right)=45\)
\(x+3=35-45\)
\(x+3=-10\)
\(x=-13\)
a, \(231-\left(x-6\right)=1339:13\)
\(\Leftrightarrow231-\left(x-6\right)=103\)
\(\Leftrightarrow x-6=128\)
\(\Leftrightarrow x=134\)
Vậy .....
b, \(70-5\left(2x-3\right)=45\)
\(\Leftrightarrow5\left(2x-3\right)=25\)
\(\Leftrightarrow2x-3=5\)
\(\Leftrightarrow2x=8\)
\(\Leftrightarrow x=4\)
Vậy ....
c, \(156-\left(x+61\right)=82\)
\(\Leftrightarrow x+61=74\)
\(\Leftrightarrow x=13\)
Vậy ....
d, \(6\left(5x+35\right)=330\)
\(\Leftrightarrow5x+35=55\)
\(\Leftrightarrow5x=20\)
\(\Leftrightarrow x=4\)
Vậy ......
e, \(936-\left(4x+24\right)=72\)
\(\Leftrightarrow4x+24=864\)
\(\Leftrightarrow4x=840\)
\(\Leftrightarrow x=210\)
Vậy ...
231-(x-6)=1339:13
237-x=103
=>x=237-103=134
Vậy x=134
70-5(2x-3)=45
70-10x+15=45
=>-10x=45-15-70=-40
=>x=4
Vậy x=4
Các caau sau tương tự nhé bn
a) \(70-5\left(2x-3\right)=45\)
\(70-10x+15=45\)
\(-10x=45-70-15\)
\(-10x=-40\)
\(x=4\)
vay \(x=4\)
b) \(156-\left(x+61\right)=82\)
\(x+61=156-82\)
\(x+61=74\)
\(x=74-61\)
\(x=13\)
vay \(x=13\)
c) \(6\left(5x+35\right)=330\)
\(30x+210=330\)
\(30x=330-210\)
\(30x=120\)
\(x=4\)
vay \(x=4\)
d) \(936-\left(4x+24\right)=72\)
\(4x+24=936-72\)
\(4x+24=864\)
\(4x=864-24\)
\(4x=840\)
\(x=210\)
vay \(x=210\)
\(70-5.\left(2x-3\right)\)\(=45\)
\(5.\left(2x-3\right)\)\(=\)\(70-45\)
\(5.\left(2x-3\right)\)\(=25\)
\(2x-3=25:5\)
\(2x-3=5\)
\(2x=8\)
\(x=8:2\)
\(x=4\)
\(156-\left(x+61\right)\)\(=82\)
\(x+61=156-82\)
\(x+61=74\)
\(x=74-61\)
\(x=13\)
\(6.\left(5x+35\right)\)\(=330\)
\(5x+35=330:6\)
\(5x+35=55\)
\(5x=55-35\)
\(5x=20\)
\(x=20:5\)
\(x=4\)
\(936-\left(4x+24\right)\)\(=72\)
\(4x+24=936-72\)
\(4x+24=864\)
\(4x=864-24\)
\(4x=840\)
\(x=840:4\)
\(x=210\)
3x=64+35
3x=99
x=99:3
x=33
70-5x+15=45
-5x=45-70-15
-5x=-40
x=(-40):(-5)
x=8
70-5(x-3)=45
5(x-3)=70-45
5(x-3)=25
x-3=25:5
x-3=5
x =5+3
x =8