A/3y+1=9y²-6y+1/3y-1
1+3y/12=1+6y/16=1+9y/4x
1+3y/12=1+6y/16=1+9y/4x
\(\frac{1+3y}{12}=\frac{1+6y}{16}=\frac{1+9y}{4x}\)
\(\frac{4x+12xy}{48x}=\frac{3x+18xy}{48x}=\frac{12+108y}{48x}\)
\(\Rightarrow4x+12xy=3x+18xy=108y+12\)
\(\Rightarrow18xy+3x-4x-12xy-108y-12=0\)
\(\Rightarrow6xy+x-108y-12=0\)
Đến đây mk chịu
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- ( 2x + 1 ) (3y - 2 ) + 6y (x -1 ) = 15 - ( 1+9y)
\(-\left(2x+1\right)\left(3y-2\right)+6y\left(x-1\right)=15-\left(1+9y\right)\)
\(\Leftrightarrow-\left(6xy-4x+3y-2\right)+6xy-6y=15-1-9y\)
\(\Leftrightarrow-6xy+4x-3y+2+6xy-6y-14+9y=0\)
\(\Leftrightarrow4x-12=0\)
\(\Leftrightarrow4x=12\)
\(\Leftrightarrow x=3\)
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Tk cho mk nha... Cảm ơn nhìu...
tìm x : 1+3y/12=1+6y/16=1+9y/4x
1+3y/12=1+6y/2x=1+9y/5x
cứu với!
113. Giải phương trình: \(\dfrac{1}{3y^2-10y}=\dfrac{6y}{9y^2-1}+\dfrac{2}{1-3y}\)
\(\dfrac{1}{3y^2-10y}=\dfrac{6y}{9y^2-1}+\dfrac{2}{1-3y}\)
\(\Leftrightarrow\dfrac{1}{3y^2-10y}=\dfrac{6y-2\left(3y+1\right)}{\left(3y-1\right)\left(3y+1\right)}\)
\(\Leftrightarrow\dfrac{1}{3y^2-10y}=\dfrac{-2}{9y^2-1}\)
\(\Leftrightarrow9y^2-1=-6y^2+20y\)
\(\Leftrightarrow15y^2-20y-1=0\)
\(\Leftrightarrow\left[{}\begin{matrix}y=\dfrac{10+\sqrt{115}}{15}\\y=\dfrac{10-\sqrt{115}}{15}\end{matrix}\right.\)
tìm x y 1+3y/12=1+6y/5x=1+9y/4x
BT13: Cho\(A=16x^4-8x^3y+7x^2y^2-9y^4\),\(B=-15x^4+3x^3y-5x^2y^2-6y^4\) và \(C=5x^3y+3x^2y^2+17y^4+1\)
a, Tính A+B-C
b, Tính A-C+B
\(a,A+B-C=16x^4-8x^3y+7x^2y^2-9y^4-15x^4+3x^3y-5x^2y^2-6y^4-5x^3y-3x^2y^2-17y^4-1\)
\(=\left(16x^4-15x^4\right)+\left(-8x^3y+3x^3y-5x^3y\right)+\left(7x^2y^2-5x^2y^2-3x^2y^2\right)+\left(-9y^4-6y^4-17y^4\right)-1\)
\(=x^4-10x^3y-x^2y^2-32y^4-1\)
\(b,A-C+B=A+B-C\) ( giống câu a )
\(a,\)
\(A+B+C\)
\(=16x^4-8x^3y+7x^2y^2-9y^4-15x^4+3x^3y-5x^2y^2-6y^4-\left(5x^3y+3x^2y^2+17y^4+1\right)\)
\(=16x^4-8x^3y+7x^2y^2-9y^4-15x^4+3x^3y-5x^2y^2-6y^4-5x^3y-3x^2y^2-17y^4-1\)
\(=\left(16x^4-15x^4\right)+\left(-9y^4-6y^4-17y^4\right)+\left(-8x^3y+3x^3y-5x^3y\right)+\left(7x^2y^2-5x^2y^2-3x^2y^2\right)-1\)
\(=x^4-32y^4-10x^3y-x^2y^2-1\)
\(b,\)
\(A-C+B=A+B-C=x^4-32y^4-10x^3y-x^2y^2-1\)
a: A+B-C
=16x^4-8x^3y+7x^2y^2-9y^4-15x^4+3x^3y-5x^2y^2-6y^4-C
=x^4-5x^3y+2x^2y^2-15y^4-5x^3y-3x^2y^2-17y^4-1
=x^4-10x^3y-x^2y^2-32y^4-1
b: A-C+B=A+B-C=x^4-10x^3y-x^2y^2-32y^4-1
Tìm x, y biết (1 + 3y)/12 = (1 + 6y)/2x = (1 + 9y)/5x
Tìm x y biết
1+3y/12=1+6y/2x=1+9y/5x