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a) \(\frac{1}{2}x+\frac{3}{5}\left(x-2\right)=3\)
0,5 x + 0,6 ( x - 2 ) = 3
0,5 x + 0.6 x - 1,2 = 3
1,1 x = 4,2
x = \(\frac{42}{11}\)
Kết luận:
b) \(\frac{1}{3}x-0,5x=0,75\)
\(\frac{1}{3}x-\frac{1}{2}x=\frac{3}{4}\)
\(-\frac{1}{6}x=\frac{3}{4}\)
\(x=-\frac{9}{2}\)
Kết luận:
c) \(\frac{3}{-2}x-0,5x=75\%\)
-1,5x - 0,5x = 0,75
-2x = 0,75
x = -0,375
Kết luận:
d) \(-\frac{2}{5}x+\frac{1}{4}=75\%-\frac{3}{4}x\)
-0,4 x + 0,25 = 0,75 - 0,75 x
-0,4 x + 0,75 x = 0,75 - 0,25
0,35 x = 0,5
x = \(\frac{10}{7}\)
Kết luận:
\(a,\frac{1}{2}x+\frac{3}{5}\left(x-2\right)=3\)
\(\frac{1}{2}x+\frac{3}{5}x-\frac{6}{5}=3\)
\(\left(\frac{1}{2}+\frac{3}{5}\right)x-\frac{6}{5}=3\)
\(\frac{11}{10}x-\frac{6}{5}=3\)
\(\frac{11}{10}x=\frac{21}{5}\)
\(x=\frac{42}{11}\)
\(b,\frac{1}{3}x-\frac{1}{2}x=\frac{3}{4}\)
\(\left(\frac{1}{3}-\frac{1}{2}\right)x=\frac{3}{4}\)
\(\frac{-1}{6}x=\frac{3}{4}\)
\(x=\frac{-9}{2}\)
\(c,\frac{3}{-2}x-\frac{1}{2}x=75\%\)
\(\left(\frac{3}{-2}-\frac{1}{2}\right)x=\frac{3}{4}\)
\(-2x=\frac{3}{4}\)
\(x=\frac{-3}{8}\)
\(\frac{-2}{5}x+\frac{1}{4}=75\%-\frac{3}{4}x\)
\(\frac{-2}{5}x+\frac{3}{4}x=\frac{3}{4}-\frac{1}{4}\)
\(\left(\frac{-2}{5}+\frac{3}{4}\right)x=\frac{1}{2}\)
\(\frac{7}{20}x=\frac{1}{2}\)
\(x=\frac{10}{7}\)
a) \(2x-\left(x+25\right)-75=-12\)
\(\Rightarrow2x-\left(x+25\right)=63\)
\(\Rightarrow2x-x-25=63\)
\(\Rightarrow x=88\)
Vậy \(x=88\)
b) \(\left(x-12\right)-15=\left(120-18\right)-\left(20+x\right)\)
\(\Rightarrow\left(x-12\right)-15=102-20-x\)
\(\Rightarrow x-12-15=82-x\)
\(\Rightarrow x-27=82-x\)
\(\Rightarrow2x=27+82\)
\(\Rightarrow2x=109\)
\(\Rightarrow x=54,5\)
Vậy \(x=54,5\)
c) \(17-\left\{-x-\left[-x-\left(-x\right)\right]\right\}=-16\)
\(\Rightarrow17+x+x+x=-16\)
\(\Rightarrow17+3x=-16\)
\(\Rightarrow3x=-33\)
\(\Rightarrow x=-11\)
Vậy \(x=-11\)
d) \(x-\left\{\left[-x+\left(x+3\right)\right]-\left[\left(x+3\right)-\left(x-2\right)\right]\right\}=0\)
\(\Rightarrow x-\left\{\left[-x+x+3\right]-\left[x+3-x+2\right]\right\}=0\)
\(\Rightarrow x+2=0\)
\(\Rightarrow x=-2\)
Vậy \(x=-2\) (Câu này hơi tắt)
\(a.x+\dfrac{1}{6}=-\dfrac{3}{8}\)
\(\Leftrightarrow x=-\dfrac{13}{24}\)
\(b.2-\left(\dfrac{3}{4}-x\right)=\dfrac{7}{12}\)
\(\Leftrightarrow2-\dfrac{3}{4}+x=\dfrac{7}{12}\)
\(\Leftrightarrow x=-\dfrac{2}{3}\)
\(c.\dfrac{1}{2}x+\dfrac{1}{8}x=\dfrac{3}{4}\)
\(\Leftrightarrow\dfrac{5}{8}x=\dfrac{3}{4}\)
\(\Leftrightarrow x=\dfrac{6}{5}\)
\(d.75\%-1\dfrac{1}{2}+0,5:\dfrac{5}{12}-\left(\dfrac{-1}{2}\right)^2\)
\(=\dfrac{75}{100}-\dfrac{3}{2}+\dfrac{1}{2}:\dfrac{5}{12}-\dfrac{1}{4}\)
\(=-\dfrac{3}{4}+\dfrac{6}{5}-\dfrac{1}{4}\)
\(=\dfrac{1}{5}\)
a) \(x+\dfrac{1}{6}=\dfrac{-3}{8}\)
\(x=\dfrac{-3}{8}-\dfrac{1}{6}\)
\(x=\dfrac{-13}{24}\)
vậy x =....
b) \(2-\left(\dfrac{3}{4}-x\right)=\dfrac{7}{12}\)
\(\dfrac{3}{4}-x=2-\dfrac{7}{12}\)
\(\dfrac{3}{4}-x=\dfrac{17}{12}\)
\(x=\dfrac{3}{4}-\dfrac{17}{12}\)
\(x=\dfrac{-2}{3}\)
vậy x =....
1) 10 - 3 ( x - 1 ) = -5
3 ( x - 1 ) = 10 - ( - 5 )
3 ( x - 1 ) = 15
x - 1 = 15 : 3
x - 1 = 5
x = 5 + 1
x = 6
2) 3x + 75 = - 15
3x = - 15 - 75
3x = - 90
x = -90 : 3
x = -30
4) 12 - ( x - 7 ) = - 8
x - 7 = 12 - (- 8 )
x - 7 = 20
x = 20 + 7
x = 27
5) x + 75 = 15
x = 15 - 75
x = -60
7) 2x + 18 = 10
2x = 10 - 18
2x = -8
x = - 8 : 2
x = -4
8) 26 - 3x = 5
3x = 26 - 5
3x = 21
x = 21: 3
x = 7
9) x - 12 = - 15
x = -15 + 12
x =-3
10 ) 24 - 2 ( x + 5 ) = 38
2 ( x+ 5 ) = 24 - 38
2 ( x + 5 ) = - 14
x + 5 = -14 : 2
x + 5 = -7
x = -7 - 5
x = -12
còn là bạn tự làm tiếp nhé ! bạn gửi nhiều cầu qua bạn chỉ nên gửi ít một thời như vậy khó có thể giải làm bạn ạ!
c: Ta có: 11+x:5=13
\(\Leftrightarrow x:5=2\)
hay x=10
d: Ta có: \(13+2\left(x+1\right)=15\)
\(\Leftrightarrow2x+2=2\)
\(\Leftrightarrow2x=0\)
hay x=0
e: Ta có: 2x+21=41
\(\Leftrightarrow2x=20\)
hay x=10
f: Ta có: \(12+3\left(x-2\right)=60\)
\(\Leftrightarrow3\left(x-2\right)=48\)
\(\Leftrightarrow x-2=16\)
hay x=18
g: Ta có: \(24x-11\cdot13=11\cdot11\)
\(\Leftrightarrow24x=11\cdot24\)
hay x=11
h: Ta có: \(17-\left(x-4\right):2=3\)
\(\Leftrightarrow\left(x-4\right):2=14\)
\(\Leftrightarrow x-4=28\)
hay x=32
tìm x , biết :
a . 1,5 . x + 2,5 = 1
\(1,5.x=-1,5\)
\(x=\dfrac{-1,5}{1,5}\)
\(x=-1\)
b . ( 0,5 . x - 1,3 ) : 0,5 = -1,7
\(0,5.x-1,3=-0,85\)
\(0,5x=-2,15\)
\(x=\dfrac{-2,15}{0,5}\)
\(x=-4,3\)
c . 1,75 .x - 1,5 . x = 0,84
\(x\left(1,75-1,5\right)=0,84\)
\(x.0,25=0,84\)
\(x=3,36\)
d . x + 75% . x + 125% = 1
\(x+\dfrac{75}{100}.x+\dfrac{125}{100}=1\)
\(x+\dfrac{3}{4}.x+\dfrac{5}{4}=1\)
\(x+\dfrac{3}{4}.x=-\dfrac{1}{4}\)
\(x.\left(1+\dfrac{3}{4}\right)=-\dfrac{1}{4}\)
\(x.1,75=-\dfrac{1}{4}\)
\(x=-\dfrac{1}{7}\)
e . x - 25% .x + 75% = 1
\(x-\dfrac{25}{100}.x+\dfrac{75}{100}=1\)
\(x-\dfrac{1}{4}.x+\dfrac{3}{4}=1\)
\(x-\dfrac{1}{4}.x=\dfrac{1}{4}\)
\(x.\left(1-\dfrac{1}{4}\right)=\dfrac{1}{4}\)
\(x.\dfrac{3}{4}=\dfrac{1}{4}\)
\(x=\dfrac{1}{3}\)
f . | x - 1,5 | = 2,37
TH1 : \(x-1,5=2,37\)
\(x=2,37+1,5\)
\(x=3,87\)
TH2 : \(x-1,5=-2,37\)
\(x=-2,37+1,5\)
\(x=-0,87\)
1. THực hiện phép tính :
a) 17 - 25 + 55 - 17
= ( 17 - 17 ) + ( -25 + 55 )
= 0 + 30 = 30
b) 25 - (-75) + 32 - (32 + 75)
= 25 + 75 + 32 - 32 - 75
= 25 + ( 75 - 75 ) + ( 32 - 32 )
= 25 + 0 + 0 = 25
c) (-5).8.(-2).3
= [(-5).(-2)].(8.3)
= 10 . 24 = 240
d) (-15) + (- 122) = - ( 15 + 122 ) = -137
e) /-127/ - 18.(5-6)
= 127 - 18.(-1)
= 127 - ( -18 ) = 127 + 18 = 145
Trả lời
1.Thực hiện phép tính :
a)17-25+55-17
=(17-17)-25+55
=0-25+55
=30
b)25-(-75)+32-(32+75)
=25+75+32-32-75
=25+(75-75)+(32-32)
=25+0+0
=25
c)(-5).8.(-2).3
=[(-5).(-2)].3.8
=10.24
=240
d)(-15)+(-122)
=(-137)
e)|-127|-18.(5-6)
=127-18.(-1)
=127.(-18)
=(-2286)
Bài 2:
a)Ư (-8)={-1;-2;-4;-8}
b)B (-11)={-11;-22;-33;-44;-55}
Bài 3:
a)-13+x=39
=>x=39+13
=>x=52
b)3x-(-17)=14
3x+17 =14
3x =14-17
3x =(-3)
x =(-3):3
x =(-1)
c)|x+9|.2=10
|x+9| =10:2
|x+9| =5
|x| =5-9
|x| =-4
Vậy: x=4 hoặc -4
d)
12=22.3
10=2.5
BCNN (12;10)=22.3.5=60
BC (12;10) = {60;120;180}
Vậy x có thể là 1 trong 3 số trên: 60;120;180.
Mình đang cần suii gấp tí mình nộp bài rồi
\(\left(2\times x-17\right):12-0,5=75\%\)
\(\left(2\times x-17\right):12-0,5=0,75\)
\(\left(2\times x-17\right):12\) \(=0,75+0,5\)
\(\left(2\times x-17\right):12\) \(=1,25\)
\(2\times x-17\) \(=1,25\times12\)
\(2\times x-17\) \(=15\)
\(2\times x\) \(=15+17\)
\(2\times x\) \(=32\)
\(x\) \(=32:2\)
\(x\) \(=16\)
Vậy \(x=16\)