Nếu (2x-7)/(4x-9)=7/9 ; (3y -6)/(4z-8)=3/4 và x;y;z khác 0 thì x/y + y/z bằng
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Nếu 2x-7/4x-9=7/9; 3y -6 / 4z -8 = 3/ 4 và x ; y ;z khác 0 thì x / y + y /z
tim x
a) (5x-3)^2-(4x-7)^2
b) (2x+7)^2=9(x+2)^2
c) (x+2)^2=9(x^2-4x+4)
b: Ta có: \(\left(2x+7\right)^2=9\left(x+2\right)^2\)
\(\Leftrightarrow\left(3x+4-2x-7\right)\left(3x+4+2x+7\right)=0\)
\(\Leftrightarrow\left(x-3\right)\left(5x+11\right)=0\)
\(\Leftrightarrow\left[{}\begin{matrix}x=3\\x=-\dfrac{11}{5}\end{matrix}\right.\)
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c: ta có: \(\left(x+2\right)^2=9\left(x^2-4x+4\right)\)
\(\Leftrightarrow\left(3x-6\right)^2-\left(x+2\right)^2=0\)
\(\Leftrightarrow\left(3x-6-x-2\right)\left(3x-6+x+2\right)=0\)
\(\Leftrightarrow\left(2x-8\right)\left(4x-4\right)=0\)
\(\Leftrightarrow\left[{}\begin{matrix}x=4\\x=1\end{matrix}\right.\)
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Tìm x, biết (4x − 9) + (5x − 7) − (2x + 6) = 7
=>4x-9+5x-7-2x-6=7
=>7x-22=7
=>7x=29
=>x=29/7
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Bài 1:a)-2x-3.( x-17 ) 34-2.( -x+25 )b)17x+3.( -16x-37 ) 2x+43-4xc){-3x+2. [ 45-x-3 ( 3x+7 ) -2x]+4x} 55g)-103-57: [ 5.( 2x-1 )2-( -9 )0 ]Bài 2:a)-5.( -x+7 )-3.( -x-5 )-4.( 12-x )+48b)7.( -x-7 )-4.( -2x-11 )7.( 4x+10 )+9c)-2.( 15-3x )-4.( -7x+8 )-5-9.( -2x+1 )d)5.( -3x-7 )-4.( -2x-11 )7.( 4x+10 )+9e)4( x-2 )2-13( -3 )2.2-11.( -3 )f)-52-( 2x-1 )3( -13 ).( -3 )
Đọc tiếp
Bài 1:
a)-2x-3.( x-17 )= 34-2.( -x+25 )
b)17x+3.( -16x-37 )= 2x+43-4x
c){-3x+2. [ 45-x-3 ( 3x+7 ) -2x]+4x} = 55
g)-103-57: [ 5.( 2x-1 )2-( -9 )0 ]
Bài 2:
a)-5.( -x+7 )-3.( -x-5 )=-4.( 12-x )+48
b)7.( -x-7 )-4.( -2x-11 )=7.( 4x+10 )+9
c)-2.( 15-3x )-4.( -7x+8 )=-5-9.( -2x+1 )
d)5.( -3x-7 )-4.( -2x-11 )=7.( 4x+10 )+9
e)4( x-2 )2-13=( -3 )2.2-11.( -3 )
f)-52-( 2x-1 )3=( -13 ).( -3 )
a; -2\(x\) - 3.(\(x-17\)) = 34 - 2.( - \(x\) + 25)
- 2\(x\) - 3\(x\) + 51 = 34 + 2\(x\) - 50
2\(x\) + 2\(x\) + 3\(x\) = - 34 + 50 + 51
7\(x\) = 67
\(x\) = 67 : 7
\(x\) = \(\dfrac{67}{7}\)
Vậy \(x\) = \(\dfrac{67}{7}\)
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b; 17\(x\) + 3.(- 16\(x\) - 37) = 2\(x\) + 43 - 4\(x\)
17\(x\) - 48\(x\) - 111 = 2\(x\) - 4\(x\) + 43
- 31\(x\) - 2\(x\) + 4\(x\) = 111 + 43
- \(x\) x (31 + 2 - 4) = 154
- \(x\) x (33 - 4) = 154
- \(x\) x 29 = 154
- \(x\) = 154 : (-29)
\(x\) = - \(\dfrac{154}{29}\)
Vậy \(x=-\dfrac{154}{29}\)
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c; {-3\(x\) + 2.[45 - \(x\) - 3(3\(x\) + 7) - 2\(x\)] + 4\(x\) } = 55
{-3\(x\) + 2.[45 - \(x\) - 9\(x\) - 21 - 2\(x\)] + 4\(x\)} = 55
{- 3\(x\) + 2.[(45 - 21) - (\(x+9x\)+2\(x\))] + 4\(x\) } = 55
{ (- 3\(x\) + 4\(x\)) + 2.[24 - 12\(x\)] } = 55
\(x\) + 48 - 24\(x\) = 55
\(x-24x\) = 55 - 48
- 23\(x\) = 7
\(x\) = 7 : - 23
\(x=-\dfrac{7}{23}\)
Vậy \(x=-\dfrac{7}{23}\)
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Xem thêm câu trả lời
Tìm x, biết:
a) 4x2-12x=-9
b) (5-2x)(2x+7)=4x2-25
c) x3+27+(x+3)(x-9)=0
d) 4(2x+7)2-9(x+3)2=0
5.(-3x-7)-4.(-2x-11)=7.(4x+10)+9
5.(-3x-7)-4.(-2x-11)=7.(4x+10)+9
⇒ - 15x - 35 + 8x + 44 = 28x + 70 + 9
⇒ - 7x + 9 = 28x + 70 + 9
⇒ - 7x - 28x = 70 + 9 - 9
⇒ - 35x = 70
⇒ x = - 5
@@ Học tốt
Chiyuki Fujito
Nếu \(\frac{2x-7}{4x-9}=\frac{7}{9};\frac{3y-6}{4z-8}=\frac{3}{4}\)vàx,y,z khác 0 thì \(\frac{x}{y}+\frac{y}{z}=...\)
1, |x-5|=|2x-9|
2, ||2x-11|-x|=8
3, |4x-7|+\(\left|\frac{7-4x}{4x-7}\right|\)=9
4, \(\frac{\left|7x^2-9x+2\right|}{5x+4}\)=2-7x
5, \(\frac{x^2-8x+15}{\left|2x^2-9x-5\right|}\)=3x-9
2/ 5*(-3x-7) -4*(-2x-11)=7*(4x+10)+9