rút gọn phân thức
a) \(\dfrac{2x^2+xy-y^2}{2x^2-3xy+y^2}=\)
b) \(\dfrac{x^2+2xy+y^2}{xy+2y^2-x}\)
a) rút gọn biểu thức\(\dfrac{x^2+3xy+2y^2}{x^3+2x^2y-xy^2-2y^3}\) rồi tính giá trị của biểu thức tại x=5 và y=3
B) phân tích đa thức 2x-2y-x^2+2xy-y^2
B) Ta có: 2x-2y-x2+2xy-y2
⇔ 2(x-y)-(x2-2xy+y2)
⇔ 2(x-y)-(x-y)2
⇔ (x-y)(2-x+y)
Đúng thì tick nhé
Bài 1: Rút gọn các phân thức sau:
a) \(\dfrac{x^3-1}{x^2+x+1}\)
b) \(\dfrac{x^2+2xy+y^2}{2x^2+xy-y^2}\)
c) \(\dfrac{ax^4-a^4x}{a^2+ax+x^2}\)
d) \(\dfrac{x^3+x^2-6x}{x^3-4x}\)
e) \(\dfrac{2x^2+xy-y^2}{2x^2-3xy+y^2}\)
Mng giúp e với ạ.E đg cần gấp có trc trưa mai đc ko ạ:)))
E cảm ơn ạ!!!
a) \(\dfrac{x^3-1}{x^2+x+1}=\dfrac{\left(x-1\right)\left(x^2+x+1\right)}{x^2+x+1}=x-1\)
b) \(\dfrac{x^2+2xy+y^2}{2x^2+xy-y^2}\)
\(=\dfrac{\left(x+y\right)^2}{x^2+xy+x^2-y^2}=\dfrac{\left(x+y\right)^2}{x\left(x+y\right)+\left(x-y\right)\left(x+y\right)}\)
\(=\dfrac{\left(x+y\right)^2}{\left(2x-y\right)\left(x+y\right)}=\dfrac{x+y}{\left(2x-y\right)}\)
c) \(\dfrac{ax^4-a^4x}{a^2+ax+x^2}\)
\(=\dfrac{ax\left(x^3-a^3\right)}{a^2+ax+x^2}\)
\(=\dfrac{ax\left(x-a\right)\left(a^2+ax+x^2\right)}{a^2+ax+x^2}\)
\(=ax\left(x-a\right)\)
rút gọn phân thức:
\(\dfrac{x^3-4x^2+4x}{x^2-4}\)
\(\dfrac{x^2y+2xy^2+y^3}{2x^2+xy-y^2}\)
1. \(\dfrac{x^3-4x^2+4x}{x^2-4}=\dfrac{x\left(x^2-4x+4\right)}{\left(x+2\right)\left(x-2\right)}=\dfrac{x\left(x-2\right)^2}{\left(x+2\right)\left(x-2\right)}=\dfrac{x\left(x-2\right)}{x+2}\)
\(\dfrac{x^2y+2xy^2+y^3}{2x^2+xy-y^2}=\dfrac{y\left(x^2+2xy+y^2\right)}{2x^2+2xy-xy-y^2}=\dfrac{y\left(x+y\right)^2}{2x\left(x+y\right)-y\left(x+y\right)}\)
\(=\dfrac{y\left(x+y\right)^2}{\left(2x-y\right)\left(x+y\right)}=\dfrac{y\left(x+y\right)}{2x-y}\)
Chứng minh các đẳng thức sau :
a) \(\dfrac{x^2y+2xy^2+y^3}{2x^2+xy-y^2}=\dfrac{xy+y^2}{2x-y}\)
b) \(\dfrac{x^2+3xy+2y^2}{x^3+2x^2y-xy^2-2y^3}=\dfrac{1}{x-y}\)
Rút gọn biểu thức :
a) \(\dfrac{x^4-xy^3}{2xy+y^2}:\dfrac{x^3+x^2y+xy^2}{2x+y}\)
b) \(\dfrac{5x^2-10xy+5y^2}{2x^2-2xy+2y^2}:\dfrac{8x-8y}{10x^3+10^3}\)
Rút gọn các phân thức sau:
a) \(\dfrac{6x^2y^2}{8xy^{ }5}\)
b) \(\dfrac{10xy^2\left(x+y\right)}{15xy\left(x+y\right)^3}\)
c) \(\dfrac{2x^2+2x
}{x+1}\)
d) \(\dfrac{x^2-xy-x+y}{x^2+xy-x-y}\)
e) \(\dfrac{36\left(x-2\right)^3}{32-16x}\)
a) \(\dfrac{6x^2y^2}{8xy^5}=\dfrac{3x}{4y^3}\)
b) \(=\dfrac{2y}{3\left(x+y\right)^2}=\dfrac{2y}{3x^2+6xy+3y^2}\)
c) \(=\dfrac{2x\left(x+1\right)}{x+1}=2x\)
d) \(=\dfrac{x\left(x-y\right)-\left(x-y\right)}{x\left(x+y\right)-\left(x+y\right)}=\dfrac{\left(x-y\right)\left(x-1\right)}{\left(x+y\right)\left(x-1\right)}=\dfrac{x-y}{x+y}\)
e) \(=\dfrac{36\left(x-2\right)^3}{-16\left(x-2\right)}=-9\left(x-2\right)^2=-9x^2+36x-36\)
cm đẳng thức\(a.\dfrac{x}{x+y}+\dfrac{4}{x^2+3xy+2y^2}+\dfrac{-3x}{x+2y}=\dfrac{-2x^2-xy+4}{\left(x+y\right)\left(x+2y\right)}\) với x ≠ -y; x ≠ -2y
b. \(\dfrac{x+y}{x-y}=\dfrac{x^2+2xy+y^2}{x^2-y^2}\)
\(a,VT=\dfrac{x^2+2xy+4-3x^2-3xy}{\left(x+y\right)\left(x+2y\right)}=\dfrac{-2x^2-xy+4}{\left(x+y\right)\left(x-2y\right)}=VP\\ b,VP=\dfrac{\left(x+y\right)^2}{\left(x-y\right)\left(x+y\right)}=\dfrac{x+y}{x-y}=VT\)
Rút gọn biểu thức:
\(a,\left(\dfrac{x}{xy-y^2}+\dfrac{2x-y}{xy-x^2}\right):\left(\dfrac{1}{x}+\dfrac{1}{y}\right)\)
\(b,\left(\dfrac{x+y}{2x-2y}-\dfrac{x-y}{2x+2y}-\dfrac{2y^2}{y-x}\right):\dfrac{2y}{x-y}\)
Rút gọn biểu thức:
\(a,\left(\dfrac{x}{xy-y^2}+\dfrac{2x-y}{xy-x^2}\right):\left(\dfrac{1}{x}+\dfrac{1}{y}\right)\)
\(b,\left(\dfrac{x+y}{2x-2y}-\dfrac{x-y}{2x+2y}-\dfrac{2y^2}{y-x}\right):\dfrac{2y}{x-y}\)
\(a,\frac{x}{xy-y^2}+\frac{2x-y}{xy-x^2}:\left(\frac{1}{x}+\frac{1}{y}\right)\)
\(=\left(\frac{x}{y\left(x-y\right)}+\frac{y-2x}{x\left(x-y\right)}\right):\left(\frac{y}{xy}+\frac{x}{xy}\right)\)
\(=\left(\frac{x-y}{x\left(x-y\right)}\right):\left(\frac{x+y}{xy}\right)\)
\(=\frac{1}{x}.\frac{xy}{x+y}=\frac{y}{x+y}\)