Hãy nhập câu hỏi của bạn vào đây, nếu là tài khoản VIP, bạn sẽ được ưu tiên trả lời.
a: =>x-2+2=x^2+2x
=>x^2+2x=x
=>x^2+x=0
=>x(x+1)=0
=>x=0(loại) hoặc x=-1(nhận)
b: =>-9(5x-8)+4(7x-12)=-6(x+18)
=>-45x+72+28x-48=-6x-108
=>-17x+24=-6x-108
=>-11x=-132
=>x=12
1)
a) \(2x-6=0\)
\(\Leftrightarrow2x=6\)
\(\Leftrightarrow x=3\)
b) \(x\times\left(x+2\right)-3\times\left(x+2\right)=0\)
\(\Leftrightarrow\left(x-3\right)\times\left(x+2\right)=0\)
\(\Leftrightarrow\orbr{\begin{cases}x-3=0\\x+2=0\end{cases}}\Leftrightarrow\orbr{\begin{cases}x=3\\x=-2\end{cases}}\)
c) \(\frac{x-6}{x+1}=\frac{x^2}{x-1}\)
nhân chéo lên, ngại chết đc
Bài 1:
\(\frac{15ab+5b^2}{9a^2-b^2}=\frac{5b\left(3a+b\right)}{\left(3a\right)^2-b^2}=\frac{5b\left(3a+b\right)}{\left(3a-b\right)\left(3a+b\right)}=\frac{5b}{3a-b}\)
\(\frac{3x^2-3y^2}{9x+9y}=\frac{3\left(x^2-y^2\right)}{9\left(x+y\right)}=\frac{\left(x-y\right)\left(x+y\right)}{3\left(x+y\right)}=\frac{x-y}{3}\)
\(\frac{m^2-4m+4}{2x-4}=\frac{\left(x-2\right)^2}{2\left(x-2\right)}=\frac{x-2}{2}\)
a: \(\Leftrightarrow\dfrac{y+5}{y\left(y-5\right)}-\dfrac{y-5}{2y\left(y+5\right)}=\dfrac{y+25}{2\left(y-5\right)\left(y+5\right)}\)
\(\Leftrightarrow2\left(y+5\right)^2-\left(y-5\right)^2=y^2+25y\)
=>\(2y^2+20y+50-y^2+10y-25=y^2+25y\)
=>30y+25=25y
=>5y=-25
=>y=-5(loại)
b: \(\Leftrightarrow x\left(x+1\right)+x\left(x-3\right)=4x\)
=>x^2+x+x^2-3x-4x=0
=>2x^2-6x=0
=>2x(x-3)=0
=>x=0(nhận) hoặc x=3(loại)
c: =>x^2-9-6(2x+7)=-13(x+3)
=>x^2-9-12x-42+13x+39=0
=>x^2+x-6=0
=>(x+3)(x-2)=0
=>x=2(nhận) hoặc x=-3(loại)
a)
\(\dfrac{x-2}{4}+\dfrac{2x-3}{3}=\dfrac{x-18}{6}\)
`<=> 3x-6+8x-12=2x-36`
`<=> 3x+8x-2x=-36+6+12`
`<=> 9x=-18`
`<=> x=-2`
b)
\(\dfrac{x+3}{x-3}+\dfrac{3-x}{x+3}=\dfrac{36}{x^2-9}\left(x\ne3;x\ne-3\right)\)
suy ra
`(x+3)^2 +(3-x)(x-3)=36`
`<=>x^2 +6x+9+3x-9-x^2 +3x=36`
`<=> x^2 -x^2 +6x+3x+3x+9-9-36=0`
`<=> 12x-36=0`
`<=> 12x=36`
`<=> x=3 (KTMĐK)
a) \(3-2x>4\)
\(\Leftrightarrow-2x>1\)
\(\Leftrightarrow x< \frac{-1}{2}\)
b) \(\frac{2}{3-x}-\frac{9}{3+x}=\frac{1}{2}\)ĐKXĐ : \(x\pm3\)
\(\Leftrightarrow\frac{-4\left(x+3\right)}{2\left(x-3\right)\left(x+3\right)}-\frac{18\left(x-3\right)}{2\left(x-3\right)\left(x+3\right)}=\frac{\left(x-3\right)\left(x+3\right)}{2\left(x-3\right)\left(x+3\right)}\)
\(\Rightarrow-4x-13-18x+54=x^2-9\)
\(\Leftrightarrow x^2+22x-50=0\)
\(\Leftrightarrow x^2+2\cdot x\cdot11+11^2-171=0\)
\(\Leftrightarrow\left(x+11\right)^2=\left(\pm\sqrt{171}\right)^2\)
\(\Leftrightarrow\orbr{\begin{cases}x=\sqrt{171}-11\\x=-\sqrt{171}-11\end{cases}}\)( thỏa )
Vậy....
\(a,\)\(3-2x>4\)
\(\Rightarrow-2x>1\)
\(\Rightarrow x< \frac{-1}{2}\)
\(a,\dfrac{2x-1}{3}-\dfrac{5x+2}{7}=x+13\\ \Rightarrow7.\left(2x-1\right)-3.\left(5x+2\right)=21.\left(x+13\right)\\ \Rightarrow14x-7-15x-6=21x+273\\\Rightarrow -x-21x=273+13\\ \Rightarrow-22x=286\\ \Rightarrow x=-13\\ b,\dfrac{3\left(x+3\right)}{4}+\dfrac{1}{2}=\dfrac{5x+9}{3}-\dfrac{7x-9}{4}=0\\ \Rightarrow9.\left(x+3\right)+6=4.\left(5x+9\right)-3.\left(7x-9\right)=0\\\Rightarrow 9x+27+6=20x+36-21x+27\\ \Rightarrow9x+33=-x+63\\ \Rightarrow10x=30\\ \Rightarrow x=3\)
\(a,\dfrac{2x-1}{3}-\dfrac{5x+2}{7}=x+13\)
\(\Rightarrow7\left(2x-1\right)-3\left(5x+2\right)-21x-273=0\)
\(\Rightarrow14x-7-15x-6-21x-273=0\)
\(\Rightarrow-22x=286\)
\(\Rightarrow x=-13\)
\(b,\dfrac{3\left(x+3\right)}{4}+\dfrac{1}{2}=\dfrac{5x+9}{3}-\dfrac{7x-9}{4}\)
\(\Rightarrow9\left(x+3\right)+6-4\left(5x+9\right)+3\left(7x-9\right)=0\)
\(\Rightarrow9x+27+6-20x-36+21x-27=0\)
\(\Rightarrow10x=30\Rightarrow x=3\)