rút gọn phân thức sau
\(\dfrac{x^6+2x^3y^3+y^6}{x^7-xy^6}\)
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\(\frac{x^6+2x^3y^3+y^6}{x^7-xy^6}=\frac{\left(x^3+y^3\right)^2}{x\left(x^6-y^6\right)}=\frac{\left(x^3+y^3\right)^2}{x\left(x^3-y^3\right)\left(x^3+y^3\right)}=\frac{x^3+y^3}{x\left(x^3-y^3\right)}\)
tôi cũng cung thiên yết nè nhưng lại là cậu bé mà thiên yết hợp với cung gì nhất vậy add friend nha
\(\frac{x^6+2x^3y^3+y^6}{x^7-xy^6}\)( ĐKXĐ tự tìm nhé *)
\(=\frac{\left(x^3\right)^2+2x^3y^3+\left(y^3\right)^2}{x\left(x^6-y^6\right)}\)
\(=\frac{\left(x^3+y^3\right)^2}{x\left[\left(x^3\right)^2-\left(y^3\right)^2\right]}\)
\(=\frac{\left[\left(x+y\right)\left(x^2-xy+y^2\right)\right]^2}{x\left(x^3-y^3\right)\left(x^3+y^3\right)}\)
\(=\frac{\left[\left(x+y\right)\left(x^2-xy+y^2\right)\right]^2}{x\left(x-y\right)\left(x^2+xy+y^2\right)\left(x+y\right)\left(x^2-xy+y^2\right)}\)
\(=\frac{\left(x+y\right)\left(x^2-xy+y^2\right)}{x\left(x-y\right)\left(x^2+xy+y^2\right)}\)
\(=\frac{x^3+y^3}{x\left(x^3-y^3\right)}=\frac{x^3+y^3}{x^4-xy^3}\)
\(\frac{x^2-5x+6}{x^2-2x}=\frac{x^2-2x-3x+6}{x.\left(x-2\right)}=\frac{x.\left(x-2\right)-3.\left(x-2\right)}{x.\left(x-2\right)}\)
\(=\frac{\left(x-3\right).\left(x-2\right)}{x.\left(x-2\right)}=\frac{x-3}{x}\)
Điều kiện \(x\ne\pm3;y\ne-2\):
\(P=\frac{2x+3y}{xy+2x-3y-6}-\frac{6-xy}{xy+2x+3y+6}-\frac{x^2+9}{x^2-9}.\)
=> \(P=\frac{2x+3y}{\left(y+2\right)\left(x-3\right)}-\frac{6-xy}{\left(y+2\right)\left(x+3\right)}-\frac{x^2+9}{\left(x-3\right)\left(x+3\right)}\)
\(P=\frac{\left(2x+3y\right)\left(x+3\right)-\left(6-xy\right)\left(x-3\right)-\left(x^2+9\right)\left(y+2\right)}{\left(y+2\right)\left(x-3\right)\left(x+3\right)}\)
\(P=\frac{2x^2+3xy+6x+9y-6x+x^2y+18-3xy-x^2y-9y-2x^2-18}{\left(y+2\right)\left(x-3\right)\left(x+3\right)}\)
\(P=\frac{0}{\left(y+2\right)\left(x-3\right)\left(x+3\right)}=0\)
=> P=0 (với mọi x khác 3, -3 và y khác -2)
b: \(=\dfrac{\left(x+3\right)^2-y^2}{2\left(x-y+3\right)}\)
\(=\dfrac{\left(x+3+y\right)\left(x+3-y\right)}{2\left(x-y+3\right)}=\dfrac{x+y+3}{2}\)
a) \(\dfrac{x^6+2x^3y^3+y^6}{x^7-xy^6}=\dfrac{\left(x^3+y^3\right)^2}{x\left(x^6-y^6\right)}\)
\(=\dfrac{\left(x^3+y^3\right)^2}{x\left(x^3-y^3\right)\left(x^3+y^3\right)}\)
\(=\dfrac{x^3+y^3}{x\left(x^3-y^3\right)}\)
b) \(\dfrac{\left(2x^2+2x\right)\left(x-2\right)^2}{\left(x^3-4x\right)\left(x+1\right)}=\dfrac{2x\left(x+1\right)\left(x-2\right)^2}{x\left(x^2-4\right)\left(x+1\right)}\)
\(=\dfrac{2x\left(x+1\right)\left(x-2\right)^2}{x\left(x-2\right)\left(x+2\right)\left(x+1\right)}\)
\(=\dfrac{2\left(x-2\right)}{x+2}\)
c) \(\dfrac{x^3-x^2y+xy^2}{x^3+y^3}=\dfrac{x\left(x^2-xy+y^2\right)}{\left(x+y\right)\left(x^2-xy+y^2\right)}\)
\(=\dfrac{x}{x+y}\)
d) \(\dfrac{a^2+b^2-c^2+2ab}{a^2-b^2+c^2+2ac}=\dfrac{\left(a^2+2ab+b^2\right)-c^2}{\left(a^2+2ac+c^2\right)-b^2}\)
\(=\dfrac{\left(a+b\right)^2-c^2}{\left(a+c\right)^2-b^2}\)
\(=\dfrac{\left(a+b-c\right)\left(a+b+c\right)}{\left(a-b+c\right)\left(a+b+c\right)}\)
\(=\dfrac{a+b-c}{a-b+c}\)
e) \(\dfrac{2x^3-7x^2-12x+45}{3x^3-19x^2+33x-9}=\dfrac{\left(x-3\right)\left(2x^2-x-15\right)}{\left(x-3\right)\left(3x^2-10x+3\right)}\)
\(=\dfrac{2x^2-x-15}{3x^2-10x+3}\)
\(=\dfrac{\left(x-3\right)\left(2x+5\right)}{\left(x-3\right)\left(3x-1\right)}\)
\(=\dfrac{2x+5}{3x-1}\)
Ta có: \(\dfrac{x^6+2x^3y^3+y^6}{x^7-xy^6}\)
\(=\dfrac{\left(x^3+y^3\right)^2}{x\left(x^6-y^6\right)}\)
\(=\dfrac{\left(x^3+y^3\right)\left(x^3+y^3\right)}{x\left(x^3+y^3\right)\left(x^3-y^3\right)}\)
\(=\dfrac{x^3+y^3}{x\left(x^3-y^3\right)}\)
\(=\dfrac{\left(x+y\right)\left(x^2-xy+y^2\right)}{x\left(x-y\right)\left(x^2+xy+y^2\right)}\)
\(\dfrac{x^6+2x^3y^3+y^6}{x^7-xy^6}=\dfrac{\left(x^3+y^3\right)^2}{x\left(x^6-y^6\right)}=\dfrac{\left(x^3+y^3\right)^2}{x\left(x^3-y^3\right)\left(x^3+y^3\right)}=\dfrac{x^3+y^3}{x\left(x^3-y^3\right)}=\dfrac{\left(x+y\right)\left(x^2-xy+y^2\right)}{\left(x^2-y^2\right)\left(x^2+y^2\right)}=\dfrac{\left(x+y\right)\left(x^2-xy+y^2\right)}{\left(x-y\right)\left(x+y\right)\left(x^2+y^2\right)}=\dfrac{x^2-xy+y^2}{x^3+xy^2-x^2y-y^3}\)