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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!!
a) 5x - 16 = 40 + x
5x -x = 40 +16
4x = 56
x = 56 : 4
x = 14
b, 4x - 10 = 15 - x
4x + x = 15 +10
4x + x = 25
5x = 25
x = 25 : 5
x = 5
a.219 - 7(x+1) = 100
7(x+1) = 219 - 100
7(x+1) = 119
x + 1 = 119 : 7
x + 1 = 17
x = 17 - 1
x = 16
b. (3x - 6 ) . 3 = 36
3x - 6 = 36 : 3
3x - 6 = 12
3x = 12 + 6
3x = 18
x = 18 : 3
x = 6
c.716 - ( x-143) = 659
x-143 = 716 - 659
x-143 = 57
x = 57 + 143
x = 200
b. 30 - [4(x-2)+15] = 3
4(x-2) + 15 = 30 - 3
4(x-2)+15 = 27
4(x-2) = 27 - 15
4(x-2) = 12
x-2 = 12 : 4
x-2 = 3
x = 2 + 3 = 5
e.[(8x - 12) : 4] .33 = 36
[(8x - 12) : 4] . 27 = 729
(8x - 12) : 4 = 729 : 27 = 27
8x - 12 = 27 . 4 = 108
8x = 108 + 12 = 120
x = 120 : 8 = 15
a) \(\Leftrightarrow7\left(x+1\right)=119\\ \Leftrightarrow x+1=17\\ \Leftrightarrow x=16\)
b) \(\Leftrightarrow9\left(x-2\right)=36\\ \Leftrightarrow x-2=4\\ \Leftrightarrow x=6\)
c) \(\Leftrightarrow x-143=57\\ \Leftrightarrow x=200\)
d) \(\Leftrightarrow4\left(x-2\right)+15=27\\ \Leftrightarrow4\left(x-2\right)=12\\ \Leftrightarrow x-2=3\\ \Leftrightarrow x=5\)
e) \(\Leftrightarrow\left(2x-3\right).4:4=3^3\\ \Leftrightarrow2x-3=27\\ \Leftrightarrow2x=24\\ \Leftrightarrow x=12\)
a)4.(x+3)-(2x-12)=x-(-11+4)
4x+12-2x+12=x+11-4
2x+24=x+7
2x-x=-24+7
x=-17
b)-(4x-13)+(5x-4)=-3-(-15+7)
-4x+13+5x-4=-3+15-7
(-4x+5x)+13-4=12-7
x+9=5
x=-4
c)(5x-3)-(-2x+4)=6x-12
5x-3+2x-4=6x-12
5x+2x-6x=3+4-12
x=-5
d)(15x+20)-(9x-3)=5x-(-12)
15x+20-9x+3=5x+12
15x-9x-5x=-20-3+12
x=-11
e,(7x+14)+(3x-8)=-(-9x+3)
7x+14+3x-8=9x-3
7x+3x-9x=-14+8-3
x=-9
a) x+15 = 20-4x
=> x=1
b) 17-x=7-6x
=> x=-2
c) -12+x=5x-20
=> x=2
d) 4x-5=15-x
=> x=4
e) 9x-7=20-6x
=>x= \(\frac{9}{5}\)
g)2.(x-10)=3.(x-20)=x-4
=> x thuộc ∅
h) (x^2+2).(x-3) <0
=> x=3,...
Đề trên lỗi nhé ae , đề đúng đây:
1. Tìm số đối của mỗi số nguyên sau: -7; 0; -4; 12; |-5|
và |5|.
2. Tính:
a) 8274 + 226 ;
b) (- 5 ) + ( -11) ; c) (- 43) + (-9)
3. Tính:
a) 17 + ( - 7) ;
b) (-96) + 64 ;
c) 75 + ( -325)
4. Tính:
a) 10- (-3) ;
b) (-21) – (-19);
c) 13 – 30 ;
d) 9 – (- 9)
5. Tính tổng:
a) (-30) + 15 + 10 + ( -15) ;
b) 17 + ( -12) + 25 – 17 ; b) 17 + ( -12) + 25 – 17 ;
c) (-14) + 250 + ( - 16) + (- 250) ;
d) ( -3) + ( - 14) + 27 + ( -10)
1. số đối: -7; 0; -4; 12; \(|-5|\); 5
là: 7; 0; 4; -12; -5; -5
2,3,4,a, 8274 + 226 = 8500
b, -5 + -11 = -16
c, -43 + -9 = -52
d, 17 + -7 = 10
e, -96 + 64 = -32
f, 75 + -325 = -250
g, 10 - (-3) = 10 + 3 = 13
h, -21 + 19 = -2
.., 13 - 30 = -17
.., 9 + 9 = 18
5, a,
-30 + 15 + 10 + -15 = -30 + 10 = 20
b, 17 + -12 + 25 - 17 = -12 + 25 = 13
c,-14 +250 - 16 - 250 = -14 + -16 = -30
d,-3 - 14 + 27 - 10 = 0
e, -14 + 250 - 16 - 250 = -14 + -16 = -30
f, -3 - 14 + 27 - 10 = 0
`[(6x-39) :7 ].4=12`
`(6x-39) :7 = 12:4`
`(6x-39) :7=3`
`(6x-39)=3 xx 7`
`6x-39= 21`
`6x=21+39`
`6x = 60`
`x=60/6`
`x=10`
____________________________________
`[(5x-12):4].33=66`
`(5x-12):4 = 66:33`
`(5x-12):4 = 2`
`5x-12=2xx4`
`5x-12=8`
`5x=8+12`
`5x = 20`
`x=20/5`
`x=4`
____________________________
`30-[4(x-2 ) +17 ] = 3`
`4.(x-2)+17=30-3`
`4.(x-2) +17=27`
`4.(x-2)=27-17`
`4.(x-2) = 10`
`x-2=10:4`
`x-2 = 5/2`
`x=5/2+2`
`x=9/2`
_________________________________
`250-10.(24-3x):15=244`
`10.(24-3x):15=250-244`
`10.(24-3x):15=6`
`10.(24-3x)=6xx15`
`10.(24-3x)=90`
`24-3x=90/10`
`24-3x=9`
`3x=24-9`
`3x=15`
`x=15/3`
`x=5`
B, [(6x - 39):7 ] .4 = 12
( 6x - 39):7 = 12: 4
6x - 39 = 21
6x = 39 + 21
6x = 60
x = 60 : 6
x = 10
6x = 42
x = 42: 6
x = 7
E, 250 - 10(24 -3x) : 15 = 244
10( 24 - 3x) : 15 = 250 - 244
10(24 - 3x) : 15 = 6
10 ( 24 - 3x) = 6x 15
10( 24- 3x) = 90
24 - 3x = 90: 10
24 - 3x = 9
3x = 24 - 9
3x = 15
x = 15: 3
x = 5
C, [(5x -12): 4].33 = 66
(5x -12) : 4 = 66: 33
( 5x - 12) : 4 = 2
5x - 12 = 8
5x = 12 + 8
5x = 20
x = 20: 5
x = 4
D, 30 - [ 4(x-2) + 17] = 3
4(x-2) + 17 = 30 - 3
4( x - 2) = 27 - 17
x - 2 = 10: 4
x - 2 = 5/2
x = 5/2 + 2
x = 9/2