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a) -2 (x+6)+6 (x-10)=8
-2.x + (-2).6 + 6.x - 6.10 = 8
-2x + (-12) + 6x - 60 = 8
-2x + 6x + [60 + (-12)] = 8
4x + 48 = 8
4x = 8 - 48
4x = -40
x = -40 : 4
x = -10
vậy_____
b) ( x-12)-15=(20-7) - (18-x)
x - 12 - 15 = 13 - 18 + x
x - 27 = -5 + x
x - x = -5 + 27
0x = 22
x = 22 : 0
=> x ∈ ∅
c)2(5+3x)+x=31
2.5 + 2.3x + x = 31
10 + 6x + x = 31
6x + x = 31 - 10
7x = 21
x = 21 : 7
x = 3
vậy_____
d) -x (x+7) ( x-4) =0
=> -x = 0 hoặc x+ 7 = 0 hoặc x - 4 = 0
=> x = 0 hoặc x = 0 - 7 hoặc x = 0 + 4
=> x = 0 hoặc x = -7 hoặc x = 4
vậy_____
e) x-96 = (443 - x) - 15
x - 96 = 443 - x - 15
x - 96 = (443 - 15) - x
x - 96 = 428 - x
x + x = 428 + 96
2x = 524
x = 524 : 2
x = 262
vậy_____
a) x - 96 = (433 - x) - 15
x - 96 = 433 - x - 15
2x = 433 - 15 + 96
2x = 514
x = 257
b) 7x (-x-10) = 0
\(\Leftrightarrow\orbr{\begin{cases}7x=0\\-x-10=0\end{cases}}\)\(\Leftrightarrow\orbr{\begin{cases}x=0\\x=-10\end{cases}}\)
c) 17 (3x - 6) (2x - 8) = 0
(3x - 6) (2x - 8) = 0
\(\Leftrightarrow\orbr{\begin{cases}3x-6=0\\2x-8=0\end{cases}}\)\(\Leftrightarrow\orbr{\begin{cases}3x=6\\2x=8\end{cases}}\)\(\Leftrightarrow\orbr{\begin{cases}x=2\\x=4\end{cases}}\)
a) x - 96 = (443 - x) - 15
x - 96 = 443 - x - 15
x + x = 443 -15 + 96
2x = 524
x = 524 : 2
x = 262
b) (x -12) - 15 = (20 - 7) - (18 + x)
x - 12 - 15 = 20 - 7 - 18 - x
x + x = 20 - 7 - 18 + 12 + 15
2x = 22
x = 22 : 2
x = 11
c) 311 - x + 82 = 46 + (x - 21)
311 - x + 82 = 46 + x - 21
-x - x = 46 - 21 - 311 - 81
-2x = -367
x = -367 : (-2)
x = 183,5
d) -(x - 3 + 85) = (x + 70 - 71) - 5
-x + 3 - 85 = x + 70 - 71 - 5
-x - x = 70 - 71 - 5 - 3 + 85
-2x = 76
x = 76 : (-2)
x = -38
e,f làm tương tự
a) x - 96 = (443 - x) - 15
x - 96 = 443 - x - 15
x + x = 443 -15 + 96
2x = 524
x = 524 : 2
x = 262
b) (x -12) - 15 = (20 - 7) - (18 + x)
x - 12 - 15 = 20 - 7 - 18 - x
x + x = 20 - 7 - 18 + 12 + 15
2x = 22
x = 22 : 2
x = 11
c) 311 - x + 82 = 46 + (x - 21)
311 - x + 82 = 46 + x - 21
-x - x = 46 - 21 - 311 - 81
-2x = -367
x = -367 : (-2)
x = 183,5
d) -(x - 3 + 85) = (x + 70 - 71) - 5
-x + 3 - 85 = x + 70 - 71 - 5
-x - x = 70 - 71 - 5 - 3 + 85
-2x = 76
x = 76 : (-2)
x = -38
e,f làm tương tự
caau 1 5.(3x-21)=0
3x-21=0
3x=21
x=7
câu2 x-90=443-x-15
x+x=443+90-15
2x=524
x=262
câu3 (3-x).(x+4)=0
=> 3- x=0 hoặc x+4=0=>x=4
x=3
\(\dfrac{11}{8}:x-\dfrac{2}{5}+-\dfrac{1}{6}=-\dfrac{1}{5}\\ =>\dfrac{11}{8}:x-\dfrac{2}{5}=-\dfrac{1}{5}-\left(-\dfrac{1}{6}\right)\\ =>\dfrac{11}{8}:x-\dfrac{2}{5}=-\dfrac{1}{5}+\dfrac{1}{6}\\ =>\dfrac{11}{8}:x-\dfrac{2}{5}=-\dfrac{6}{30}+\dfrac{5}{30}\\ =>\dfrac{11}{8}:x-\dfrac{2}{5}=-\dfrac{1}{30}\\ =>\dfrac{11}{8}:x=-\dfrac{1}{30}+\dfrac{2}{5}\\ =>\dfrac{11}{8}:x=-\dfrac{1}{30}+\dfrac{12}{30}\\ =>\dfrac{11}{8}:x=\dfrac{11}{30}\\ =>x=\dfrac{11}{8}:\dfrac{11}{30}\\ =>x=\dfrac{11}{8}.\dfrac{30}{11}\\ =>x=\dfrac{30}{8}\\ =>x=\dfrac{15}{4}\\ \dfrac{4}{7}x-\dfrac{1}{3}x+\left(-\dfrac{16}{21}\right)=-\dfrac{2}{3}\\ =>\left(\dfrac{4}{7}-\dfrac{1}{3}\right)x=-\dfrac{2}{3}-\left(-\dfrac{16}{21}\right)\\ =>\left(\dfrac{12}{21}-\dfrac{7}{21}\right)x=-\dfrac{2}{3}+\dfrac{16}{21}\\ =>\dfrac{5}{21}x=-\dfrac{14}{21}+\dfrac{16}{21}\\ =>\dfrac{5}{21}x=\dfrac{2}{21}\\ =>x=\dfrac{2}{21}:\dfrac{5}{21}\)
\(=>x=\dfrac{2}{21}.\dfrac{21}{5}\\ =>x=\dfrac{2}{5}\\ -\dfrac{11}{12}x+\dfrac{15}{2}\left(x+-\dfrac{1}{5}\right)=\dfrac{67}{8}\\ =>-\dfrac{11}{12}x+\dfrac{15}{2}.x-\dfrac{1}{5}=\dfrac{67}{8}\\ =>\left(-\dfrac{11}{12}+\dfrac{15}{2}\right)x=\dfrac{67}{8}+\dfrac{1}{5}\\ =>\left(-\dfrac{11}{12}+\dfrac{90}{12}\right)x=\dfrac{335}{40}+\dfrac{8}{40}\\ =>\dfrac{79}{12}x=\dfrac{343}{40}\\ =>x=\dfrac{343}{40}:\dfrac{79}{12}\\ =>x=\dfrac{343}{40}.\dfrac{12}{79}\\ =>x=\dfrac{343.12}{40.79}\\ =>x=\dfrac{343.3}{10.79}\\ =>x=\dfrac{1029}{790}\)
1) - 538 - ( - 830 ) = - 1368
2) - 8. (- 30) = - 240
3) -8 . 9 - ( - 48 ) = -72 - ( -48) = - 120
4) - 36 . ( - 264 ) = 9504
5) 111 - 611 = - 500
6) ( - 8 ). ( - 125 ) = 1000
7) 154 + (-54) = 100
8) ( - 134 ) + (-66) = - 200
9) x thuộc { -19, -18,...,20 }
Bạn cố gắng làm hết nhé minh có việc phải đi rồi!
a, (x-12) -15 = (20-7) - (18+x)
<=> x - 12 - 15 = 13 - 18 - x
<=> 2x = 22
<=> x = 11
b, x- 96 = ( 443 - x) - 15
<=> x - 96 = 443 - x - 15
<=> 2x = 524
<=> x = 262
c, 311 - x + 82 = 46 + ( x- 21)
<=> 311 - x + 82 = 46 + x - 21
<=> 2x = 368
<=> x = 184
e, ( - x + 821 + 534 ) = 499 + ( x-84)
<=> - x + 821 + 534 = 499 + x - 84
<=> 2x = 940
<=> x = 470
f, x + 96 = ( 443 - x) - 447
<=> x + 96 = 443 - x - 447
<=> 2x = - 100
<=> x = - 50
a, x - 96 = ( 443 - x ) - 15
x - 96 = 443 - x - 15
x - 96 = 428 - x
x + x = 428 + 96
2x = 524
x = 262
b, ( x - 12 ) - 15 = ( 20 - 7 ) - ( 18 - x )
x - 12 - 15 = 13 - 18 + x
x - 27 = - 5 + x
x - x = - 5 + 27
0x = 22
=> ko có giá trị nào thõa mãn
c, 353 - x = 46 + ( 3x - 21 )
353 - x = 46 + 3x - 21
353 - x = 25 + 3x
- x - 3x = 25 - 353
- 4x = - 328
x = 82
d, - ( x + 81 ) = ( 2x +12 ) - ( 5 + x )
- x - 81 = 2x + 12 - 5 - x
- x - 81 = x + 7
- x - x = 7 + 81
- 2x = 88
x = - 44
e, ( - x + 821 + 534 ) = 499 + ( x - 84 )
- x + 1355 = 499 + x - 84
- x - x = 499 - 84 - 1355
- 2x = - 940
x = 470
g, x + 53 = ( 400 - 9x ) - 447
x + 53 = 400 - 9x - 447
x + 53 = - 47 - 9x
x + 9x = - 47 - 53
10x = -100
x = - 10