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a) \(\dfrac{2}{3}x-\dfrac{1}{2}=\dfrac{1}{10}\)
\(\dfrac{2}{3}x=\dfrac{1}{10}+\dfrac{1}{2}=\dfrac{3}{5}\)
\(x=\dfrac{3}{5}:\dfrac{2}{3}=\dfrac{9}{10}\)
b) \(\dfrac{39}{7}:x=13\)
\(x=\dfrac{\dfrac{39}{7}}{13}=\dfrac{3}{7}\)
c) \(\left(\dfrac{14}{5}x-50\right):\dfrac{2}{3}=51\)
\(\dfrac{14}{5}x-50=51\cdot\dfrac{2}{3}=34\)
\(\dfrac{14}{5}x=34+50=84\)
\(x=\dfrac{84}{\dfrac{14}{5}}=30\)
d) \(\left(x+\dfrac{1}{2}\right)\left(\dfrac{2}{3}-2x\right)=0\)
\(\Leftrightarrow\left[{}\begin{matrix}x+\dfrac{1}{2}=0\\\dfrac{2}{3}-2x=0\end{matrix}\right.\Leftrightarrow\left[{}\begin{matrix}x=-\dfrac{1}{2}\\x=\dfrac{1}{3}\end{matrix}\right.\)
e) \(\dfrac{2}{3}x-\dfrac{1}{2}x=\dfrac{5}{12}\)
\(\dfrac{1}{6}x=\dfrac{5}{12}\)
\(x=\dfrac{5}{12}:\dfrac{1}{6}=\dfrac{5}{2}\)
g) \(\left(x\cdot\dfrac{44}{7}+\dfrac{3}{7}\right)\dfrac{11}{5}-\dfrac{3}{7}=-2\)
\(\left(x\cdot\dfrac{44}{7}+\dfrac{3}{7}\right)\cdot\dfrac{11}{5}=-2+\dfrac{3}{7}=-\dfrac{11}{7}\)
\(x\cdot\dfrac{44}{7}+\dfrac{3}{7}=-\dfrac{11}{7}:\dfrac{11}{5}=-\dfrac{5}{7}\)
\(\dfrac{44}{7}x=-\dfrac{5}{7}-\dfrac{3}{7}=-\dfrac{8}{7}\)
\(x=-\dfrac{8}{7}:\dfrac{44}{7}=-\dfrac{2}{11}\)
h) \(\dfrac{13}{4}x+\left(-\dfrac{7}{6}\right)x-\dfrac{5}{3}=\dfrac{5}{12}\)
\(\dfrac{25}{12}x-\dfrac{5}{3}=\dfrac{5}{12}\)
\(\dfrac{25}{12}x=\dfrac{5}{12}+\dfrac{5}{3}=\dfrac{25}{12}\)
\(x=1\)
Mỏi tay woa bn làm nốt nha!!
1/ -7264 + (1543 + 7264)
=-7264 + 1543 + 7264=1543
2/ (144 – 97) – 144
=144-97-144=-97
3/ (-145) – (18 – 145)(Vì có dấu trừ ở trước ngoặc nên p đổi dấu)
=-145-18+145=-18
4/ 111 + (-11 + 27)
=111-11+27=137
a) (125 -679 + 145 ) - ( 125 - 679 )=125 -679+145-125+679=145
b)(x - 29 ) - ( 17 - 38 ) = -9
<=> x-29 -17+38=-9
<=>x=-1
c)( x + 5 ) + ( x - 9 ) = x + 2
<=>x+5+x-9=x+2
<=>x+x-x=2+9-5
<=>x=6
d) ( 27 - x )+ ( 15 + x ) = x - 24
<=> 27-x+15+x-x=-24
<=> -x=-66
<=>x=66
e) -359 + 181 + ( -123 ) + 350 + ( -172 ) = (181 +350)-(359+172) -123 =531-531-123=-123
f) 13 - 12 + 11 + 10 - 9 + 8 - 7 -6 + 5 - 4 + 3 + 2 -1=( 13 - 12) +11 + (10 - 9)+(8-7)-6+(5-4)+3+(2-1)=1+11+1+1-6+1+3+1=13
a, (125 -679 + 145 ) - ( 125 - 679 )
= 125 - 679 + 145 - 125 + 679
= ( 125 - 125 ) + ( -679 + 679 ) + 145
= 0 + 0 +145
= 145
b, (x - 29 ) - ( 17 - 38 ) = -9
x - 29 - 17 + 38 = -9
x - 29 - 17 = -9 - 38
x - 29 - 17 = -47
x - 29 = -47 + 17
x - 29 = -30
x = -30 + 29
x = -1
Vậy x = -1
c, ( x + 5 ) + ( x - 9 ) = x + 2
x + 5 + x - 9 = x + 2
x - x + 14 = x + 2
14 = x + 2
x = 14 - 2
x = 12
Vậy x = 12
d, ( 27 - x )+ ( 15 + x ) = x - 24
27 - x + 15 + x = x - 24
42 + ( -x + x ) = x - 24
42 = x - 24
x = 24 + 42
x = 66
Vậy x = 66
e, -359 + 181 + ( -123 ) + 350 + ( -172 )
= ( -359 + 350 ) + [ 181 + ( -172 ) ] + ( -123)
= (-9) + 9 + ( -123 )
= 0 + ( -123)
= (-123)
g , 13 - 12 + 11 + 10 - 9 + 8 - 7 -6 + 5 - 4 + 3 + 2 -1
= ( 13 - 12 ) + ( 10 - 9 ) + ( 8 - 7 ) + ( 5 - 4 ) + ( 2 - 1 ) + ( 11 - 6 + 3)
= 1 + 1 + 1 + 1 + 1 + 8
= 1. 5 + 8
= 5 + 8
= 13
1).( 27,56 x 35 ) + ( 27,56 x 67 ) - ( 27,56 x 2)
= (964 + 1846,52) - 55,12
=2810,52 - 55,12
= 2755,4
2).( 4x 35 ) x ( 25 x 5 ) x 2
= ( 140 x 125 ) x2
= 17500 x 2
=35000
4). 3/10
5). 1188
6). 61/6
1) = 35 . 18 - 35 . 18 = 0
2) = 45 - 5 . 12 + 5 . 9 = 45 - 60 + 45 = 30
3) = 24 . 16 - 24 . 5 - 16 . 24 - 16 . 5
= (24 . 16 - 16 . 24) - 5 (24 - 16)
= 0 - 5 . 8 = 0 - 40 = -40
4) = 29 . 19 - 29 . 13 - 19 . 29 - 19 . 13
= (29 . 19 - 29 . 19) - 13 (29 - 19)
= 0 - 13 . 10 = 0 - 130 = -130
5) = 31 . (-18) + 31 . (-81) - 31 . 1
= 31 [(-18) + (-81) - 1]
= 31 . (-100) = -3100
6) = (-12) . 47 + (-12) . 52 + (-12). 1
= (-12) . (47 + 52 + 1)
= (-12) . 100 = -1200
7) = 13 . 45 - 3 . 45
= 45 (13 - 3)
= 45 . 10 = 450
8) = (-48) + 48 . (-78) + 48 . (-21)
= (-48) . 1 + 48 . (-78) + 48 . (-21)
= 48 . (-1) + 48 . (-78) + 48 . (-21)
= 48 . [(-1) + (-78) + (-21)]
= 48 . (-100) = -4800
1) 35x18-5x7x18
= 35x18-35x18
= 35x(18-18)
= 35x0=0
3) 24.(16-5)-16.(24-5)
= 24.16-24.5-16.24-16.5
=[24.16-16.24]-[24.5-16.5]
= [ 24. (16-16)]- [(24-16).5]
= [24.0]-[8.5]
= 0-40=-40
4) 29.(19-13)-19.(29-13)
=29.19-29.13-19.29-19.13
=[ 29.19-19.29]-[ 29.13-19.13]
= [ 29.(19-19)]-[(29-19).13]
=[29.0]-[10.13]
= 0-130= -130
5) 31.(-18)+31.(-81)-31
= 31.(-18)+31.(-81)-31.1
= 31.[(-18)+(-81)-1]
=31.(-100)
= -3100
6);7);8 tương tự 4);5);6)
a) 3(x - 2) + 150 = 204
=> 3(x - 2) = 204 - 150
=>3(x - 2) = 54
=> x - 2 = 54 : 3
=> x - 2 = 18
=> x = 18 + 2
=> x = 20
b) (x - 13) : 5 = 12
=> x - 13 = 12 x 5
=> x - 13 = 60
=> x = 60 + 13
=> x = 73
3 ( x - 2 ) + 150 = 204
\(3\left(x-3\right)=54\)
\(\left(x-3\right)=18\)
\(x=21\)
( x - 13 ) : 5 = 12
\(x-13=60\)
\(x=73\)
24 + 3 ( 5 - x ) =27
\(3\left(5-x\right)=3\)
\(5-x=1\)
\(x=4\)