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\(4\left(2x+9\right)+\left(-8x+3\right)-\left(x-3\right)=0\)
\(\Rightarrow8x+38-8x+3-x+3=0\)
\(\Rightarrow8x-8x-x=0-3-3-38\)
\(\Rightarrow-x=-44\)
\(\Rightarrow x=44\)
4(2x + 9) + (-8x + 3) - (x - 3) = 0
=> 8x + 36 - 8x + 3 - x + 3 = 0
=> -x + 42 = 0
=> -x = -42
=> x = 42
a) 2/3x +1/2 = 1/10
=> 2/3x = 1/10 - 1/2
2/3x = -2/5
=> x = -2/5 : 2/3
x = -3/5
b) (4,5 - 2x) : 3/4 = \(1\frac{1}{3}=\frac{4}{3}\)
=> 4,5 - 2x = 4/3 x 3/4
4,5 - 2x = 1
-2x = 4,5 - 1
-2x = 3,5
=> x = 3,5 : (-2)
x = - 1,75
c) x/4 = 5/20
=> x = 5/20 x 4
x = 1
d) ?????
2/3x+1/2=1/10
<=>2/3x=1/10-1/2
<=>2/3x=-2/10
=>x=-2/10 chia 2/3=-3/10
ý kia tương tự
a,x+3:2x-1=2:5
<=>x+\(\frac{3}{2}x\)-1=\(\frac{2}{5}\)
<=>x(\(\frac{3}{2}\)+1)-1=\(\frac{2}{5}\)
<=>\(\frac{5}{2}x\)=\(\frac{2}{5}+1\)
<=>\(\frac{5}{2}x\)=\(\frac{7}{5}\)
<=>x=\(\frac{14}{25}\)
b,-x:4=-9:x
<=>-\(\frac{x}{4}\)=-\(\frac{9}{x}\)
<=>x2=34
<=>x=\(\sqrt{34}\)
(mình học lớp 8,chỗ nào bạn ko hiểu kb hỏi mình nha :D)
a) \(\frac{x+3}{2x-1}=\frac{2}{5}\)
\(\Leftrightarrow\)\(5.\left(x+3\right)=2.\left(2x-1\right)\)
\(\Leftrightarrow\)\(5x+15=4x-2\)
\(\Leftrightarrow\)\(5x-4x=-2-15\)
\(\Leftrightarrow\)\(x=-17\)
Vậy \(x=-17\)
A)Ta có:\(\frac{x+3}{2x-1}=\frac{2}{5}\)
=>(x+3).5 = (2x-1).2
=>5x+15 = 4x-2
Từ đây ta thực hiện phép chuyển vế
=>5x-4x=-2-15
=>x=-17
B)\(\frac{-x}{4}=\frac{-9}{x}\)
=>\(\frac{x}{-4}=\frac{-9}{x}\)
=>x.x=-9.(-4)
=>x\(^2\)=36
=>x=6 hoặc -6
\(3\left(x-1\right)-2\left(x+2\right)=3\left(x+2\right)-2x\left(2+3x\right)\)
\(\Rightarrow3\left(x-1\right)-3\left(x+2\right)=2\left(x+2\right)-2x\left(2+3x\right)\)
\(\Rightarrow3\left(x-1-x-2\right)=2\left(x+2\right)-2\left(2x+3x^2\right)\)
\(\Rightarrow3\left(-3\right)=2\left(x+2-2x-3x^2\right)\)
\(\Rightarrow-9=2\left(2-x-3x^2\right)\)
\(\Rightarrow2-x-3x^2=-4,5\)
\(\Rightarrow x-3x^2=6,5\)(hình như sai đề)
a) x+30%x=-1.31
=> 100%x+30%x=-1.31
=>x.(100%+30%)=-1.31
=>x.13/10=-1.31=-1.31:13/10=-131/130
b) (x-1/2):1/3+5/7=9+5/7
=>(x-1/2).3+5/7=68/7
=>(x-1/2).3=68/7-5/7=9
=>x-1/2=9:3=3
=>x=3+1/2=3 1/2( hỗn số)
c) 1/2x-3/4=14/9.3/7
=>1/2x-3/4=2/3
=>1/2x=2/3+3/4=17/12
x=17/12:1/2=17/12.2=17/6
d) - 5/6 -x = 7/12+ -1/3
=>- 5/6 -x = 7/12+ -4/12=1/4
=> x = -5/6 -1/4=-13/12
e) x + 3/-15 = 1/3
=> x= 1/3 - -3/15 =1/3+3/15
=> x=5/15 + 3/15=8/15
f) (4,5 -2 x). (-1 4/7)=11/14
=> 4,5 -2x=11/14 : -3/7=11/14. -7/3=-11/6
=>-2x=-11/6-9/2= -11/6 -27/6 =-19/3
=>x= -19/3: -2x=19/6
Chúc bn thi HKII tốt!!!
a)\(x-15\%x=\frac{1}{3}\)
\(x.\left(1-15\%\right)=\frac{1}{3}\)
\(x.\frac{-280}{3}=\frac{1}{3}\)
\(x=\frac{1}{3}:\frac{-280}{3}\)
\(x=\frac{-1}{280}\)
Vậy \(x=\frac{-1}{280}\)
b)\(\frac{4}{5}x-x-\frac{3}{2}x+\frac{6}{5}=\frac{1}{2}-\frac{4}{3}\)
\(-\frac{17}{10}x+\frac{6}{5}=\frac{-5}{6}\)
\(-\frac{17}{10}x=-\frac{5}{6}-\frac{6}{5}\)
\(-\frac{17}{10}x=\frac{-61}{30}\)
\(x=\frac{-61}{30}:\frac{-17}{10}\)
\(x=\frac{61}{51}\)
Vậy \(x=\frac{61}{51}\)