\(\dfrac{x^2+3xy}{x^2-9y^2}+\dfrac{2x^2-5xy-3y^2}{x^2-6xy+9y^2}=\dfrac{3x^2+2xy+3xz+6yz}{x^2-3yz+xz-3xy}\)
Chứng minh đẳng thức trên
Những câu hỏi liên quan
c/m dang thuc : (x^2 +3xy)/(x^2 - 9y^2) + (2x^2 -5xy-3y^2)/(x^2-6xy+9y^2)= (3x^2 +2xy+3xz +6yz)/(xz -3yz +z^2-3xy)
c/m dang thuc : (x^2 +3xy)/(x^2 - 9y^2) + (2x^2 -5xy-3y^2)/(x^2-6xy+9y^2)= (3x^2 +2xy+3xz +6yz)/(xz -3yz +z^2-3xy)
(2xy: x^2 - y^2 + x-y : 2x + 2y) : x+y:2x + y:y-x
x^2+3xy: x^2 - 9y^2 + 2x^2 - 5xy- 3y^2 : 6xy - x^2- 9y^2 - x^2+ xz + xy + yz: 3yz - x^2 - xz + 3xy
chứng minh đẳng thức sau
a,\(\frac{x^2+3xy}{x^2-9y^2}+\frac{2x^2-5xy-3y^2}{6xy-x^2-9y^2}=\frac{x^2+xz+xy+yz}{3yz-x^2-xz+3xy}\)
b,\(\frac{y-z}{\left(x-y\right)\left(x-z\right)}+\frac{z-x}{\left(y-z\right)\left(y-x\right)}+\frac{x-y}{\left(z-x\right)\left(z-y\right)}=\frac{2}{x-y}+\frac{2}{y-z}+\frac{2}{z-x}\)
Tính:
\(a,\dfrac{x+2}{x-1}-\dfrac{x-9}{1-x}-\dfrac{x-9}{1-x}\)
\(b,\dfrac{x^2-9y^2}{x^2y}:\dfrac{xz-3yz}{3xy}\)
\(c,\dfrac{4\left(x+3\right)}{3x-1}:\dfrac{x^2+3x}{3x-1}\)
\(\frac{4.\left(x+3\right)}{3x-1}:\frac{x^2+3x}{3x-1}=\frac{4.\left(x+3\right)}{\left(3x-1\right)}\cdot\frac{\left(3x-1\right)}{x^2+3x}=\frac{4.\left(x+3\right)}{x.\left(x+3\right)}=\frac{4}{x}\)
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\(a,\frac{x+2}{x-1}-\frac{x-9}{1-x}-\frac{x-9}{1-x}\)
\(=\frac{-x-2}{1-x}-\frac{x-9}{1-x}-\frac{x-9}{1-x}\)
\(=\frac{-x-2}{1-x}+\frac{-\left(x-9\right)}{1-x}+\frac{-\left(x-9\right)}{1-x}\)
\(=\frac{-x-2-x+9-x+9}{1-x}=\frac{-3x+16}{1-x}\)
Câu b,c mk chưa học, bn thông cảm
Còn câu a, nếu sai thì xin lượng thứ :))
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ĐK: \(x\ne1\)
\(\frac{x+2}{x-1}-\frac{x-9}{1-x}-\frac{x-9}{1-x}=\frac{x+2}{x-1}-\left(\frac{x-9}{1-x}+\frac{x-9}{1-x}\right)\)
\(=\frac{x+2}{x-1}-\frac{2\left(x-9\right)}{1-x}=\frac{x+2}{x-1}-\frac{2x-18}{1-x}\)
\(=\frac{x+2}{x-1}-\frac{\left(-1\right)\left(2x-18\right)}{\left(-1\right)\left(1-x\right)}=\frac{x+2}{x-1}-\frac{18-2x}{x-1}\)
\(=\frac{x+2-18+2x}{x-1}=\frac{3x-16}{x-1}\)
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Xem thêm câu trả lời
Phân tích đa thức sau thành nhân tử
9y^3-y
8y^3-2y(1-2y)^2
2x^3-8x^2+8x
2x^4-6x^3+6x^2-2x
x^3-6x^2y+9xy^2-x
5x^4-15x^3y+15x^2y^2-5xy^3-5x
3x^2+3xy-x-y
6xy-x^2-y^2+25
7m-7n-m^2+2mn-n^2
3xy-3xz+2xyz-xy^2-xz^2
a)\(9y^3-y\)
\(=y\left(9y^2-1\right)\)
\(=y\left(3y-1\right)\left(3y+1\right)\)
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\(9y^3-y=y\left(9y^2-1\right)=y\left(3y+1\right)\left(3y-1\right)\)
\(8y^3-2y\left(1-2y\right)^2=2y\left[\left(2y\right)^2-\left(1-2y\right)^2\right]=2y\left(4y-1\right)\)
\(2x^3-8x^2+8x=2x\left(x^2-4x+4\right)=2x\left(x-2\right)^2\)
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\(2x^4-6x^3+6x^2-2x=2x\left(x^3-3x^2+3x-1\right)=2x\left(x-1\right)^3\)\(x^3-8x^2+8x=x\left(x^2-8x+8\right)\)
\(5x^4-15x^3y+15x^2y^2-5xy^3-5x=5x\left(x^3-3x^2y+3xy^2-y^3-1\right)=5x\left[\left(x-y\right)^3-1\right]=5x\left(x-y-1\right)\left(x^2-2xy+y^2+x-y+1\right)\)
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Xem thêm câu trả lời
Tính:
\(a,\dfrac{x+2}{x-1}-\dfrac{x-9}{1-x}-\dfrac{x-9}{1-x}\)
\(b,\dfrac{x^2-9y^2}{x^2y}:\dfrac{xz-3yz}{3xy}\)
\(c,\dfrac{4\left(x+3\right)}{3x-1}:\dfrac{x^2+3x}{3x-1}\)
Lời giải:
a)
\(\frac{x+2}{x-1}-\frac{x-9}{1-x}-\frac{x-9}{1-x}=\frac{x+2}{x-1}-\frac{2(x-9)}{1-x}\)
\(=\frac{x+2}{x-1}+\frac{2(x-9)}{x-1}=\frac{x+2+2(x-9)}{x-1}=\frac{3x-16}{x-1}\)
b)
\(\frac{x^2-9y^2}{x^2y}: \frac{xz-3yz}{3xy}=\frac{x^2-9y^2}{x^2y}.\frac{3xy}{xz-3yz}\)
\(=\frac{(x-3y)(x+3y)}{x^2y}.\frac{3xy}{z(x-3y)}=\frac{3(x+3y)}{xz}\)
c) \(\frac{4(x+3)}{3x-1}:\frac{x^2+3x}{3x-1}=\frac{4(x+3)}{3x-1}.\frac{3x-1}{x^2+3x}=\frac{4(x+3)}{x^2+3x}=\frac{4(x+3)}{x(x+3)}=\frac{4}{x}\)
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A dfrac{5xy^2-3z}{3xy}+dfrac{4x^2y+3z}{3xy}B dfrac{3y+5}{y-1}+dfrac{-y^2-4y}{1-y}+dfrac{y^2+y+7}{y-1}C dfrac{6x}{x^2-9}+dfrac{5x}{x-3}+dfrac{x}{x+3}D dfrac{1-3x}{2x}+dfrac{3x-2}{2x-1}+dfrac{3x-2}{2x-4x^2}E dfrac{x^3+2x}{x^3+1}+dfrac{2x}{x^2-x+1}+dfrac{1}{x+1}
Đọc tiếp
A = \(\dfrac{5xy^2-3z}{3xy}+\dfrac{4x^2y+3z}{3xy}\)
B = \(\dfrac{3y+5}{y-1}+\dfrac{-y^2-4y}{1-y}+\dfrac{y^2+y+7}{y-1}\)
C = \(\dfrac{6x}{x^2-9}+\dfrac{5x}{x-3}+\dfrac{x}{x+3}\)
D = \(\dfrac{1-3x}{2x}+\dfrac{3x-2}{2x-1}+\dfrac{3x-2}{2x-4x^2}\)
E = \(\dfrac{x^3+2x}{x^3+1}+\dfrac{2x}{x^2-x+1}+\dfrac{1}{x+1}\)
b: \(B=\dfrac{3y+5}{y-1}-\dfrac{-y^2-4y}{y-1}+\dfrac{y^2+y+7}{y-1}\)
\(=\dfrac{3y+5+y^2+4y+y^2+y+7}{y-1}\)
\(=\dfrac{2y^2+8y+12}{y-1}\)
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\(\dfrac{x+9y}{x^2-9y^2}\) - \(\dfrac{3y}{x^2+3xy}\)
\(\dfrac{x+9y}{x^2-9y^2}-\dfrac{3y}{x^2+3xy}\)
\(=\dfrac{x+9y}{\left(x-3y\right)\left(x+3y\right)}-\dfrac{3y}{x\left(x+3y\right)}\)
\(=\dfrac{x\left(x+9y\right)-3y\left(x-3y\right)}{x\left(x-3y\right)\left(x+3y\right)}\)
\(=\dfrac{x^2-6xy+9y^2}{x\left(x-3y\right)\left(x+3y\right)}\)
\(=\dfrac{\left(x-3y\right)^2}{x\left(x-3y\right)\left(x+3y\right)}\)
\(=\dfrac{x-3y}{x\left(x+3y\right)}\)
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