Sửađề: \(\dfrac{1}{x+2}+\dfrac{1}{\left(x+2\right)\left(4x+7\right)}\)
\(=\dfrac{4x+7+1}{\left(x+2\right)\left(4x+7\right)}=\dfrac{4}{4x+7}\)
\(\dfrac{y}{2x^2-xy}+\dfrac{4x}{y^2-2xy}\)
\(\dfrac{1}{x+2}+\dfrac{3}{x^2-4}+\dfrac{x-14}{\left(x^2+4x+4\right).\left(x-2\right)}\)
\(\dfrac{1}{x+2}+\dfrac{1}{\left(x+2\right).\left(4x+7\right)}\)
\(\dfrac{1}{x+3}+\dfrac{1}{\left(x+3\right).\left(x+2\right)}+\dfrac{1}{\left(x+2\right).\left(4x+7\right)}\)
Làm các phép tính sau :
a) \(\dfrac{y}{2x^2-xy}+\dfrac{4x}{y^2-2xy}\)
b) \(\dfrac{1}{x+2}+\dfrac{3}{x^2-4}+\dfrac{x-14}{\left(x^2+4x+4\right)\left(x-2\right)}\)
c) \(\dfrac{1}{x+2}+\dfrac{1}{\left(x+2\right)\left(4x+7\right)}\)
d) \(\dfrac{1}{x+3}+\dfrac{1}{\left(x+3\right)\left(x+2\right)}+\dfrac{1}{\left(x+2\right)\left(4x+7\right)}\)
Thực hiện phép cộng các phân thức sau:
\(\dfrac{5x-1}{3x^2y}+\dfrac{x+1}{3x^2y}\\ \dfrac{7}{12xy^2}+\dfrac{11}{18x^3y}\\ \dfrac{x}{x+2}+\dfrac{7x-16}{\left(x+2\right)\left(4x-7\right)}\)
Cộng các phân thức :
a) \(\dfrac{1}{\left(x-y\right)\left(y-z\right)}+\dfrac{1}{\left(y-z\right)\left(z-x\right)}+\dfrac{1}{\left(z-x\right)\left(x-y\right)}\)
b) \(\dfrac{4}{\left(y-x\right)\left(z-x\right)}+\dfrac{3}{\left(y-x\right)\left(y-z\right)}+\dfrac{3}{\left(y-z\right)\left(x-z\right)}\)
c) \(\dfrac{1}{x\left(x-y\right)\left(x-z\right)}+\dfrac{1}{y\left(y-z\right)\left(y-x\right)}+\dfrac{1}{z\left(z-x\right)\left(z-y\right)}\)
Tìm a b c : \(\dfrac{a}{\left(x-1\right)\left(x+2\right)}+\dfrac{b}{\left(x+1\right)\left(x+2\right)}+\dfrac{c}{\left(x+2\right)}=\dfrac{4x^2+2x}{\left(x+2\right)\left(x^2-1\right)}\)
\(\dfrac{a}{\left(x-1\right)\left(x+2\right)}\)+\(\dfrac{b}{\left(x+1\right)\left(x+2\right)}\)+\(\dfrac{c}{x+2}\)= \(\dfrac{4x^2+2x}{\left(x+2\right)\left(x^2+1\right)}\)
Chứng minh đẳng thức:
a) \(\dfrac{y}{\left(x-y\right)\left(y-z\right)}+\dfrac{z}{\left(y-z\right)\left(z-x\right)}+\dfrac{x}{\left(z-x\right)\left(x-y\right)=0}\)
b) \(\dfrac{x^2}{\left(x-y\right)\left(y-z\right)}+\dfrac{y^2}{\left(y-z\right)\left(y-x\right)}+\dfrac{z^2}{\left(z-x\right)\left(z-y\right)=1}\)
c) \(\dfrac{1}{x\left(x-y\right)\left(x-z\right)}+\dfrac{1}{y\left(y-z\right)\left(y-x\right)}+\dfrac{1}{z\left(z-x\right)\left(z-y\right)}=\dfrac{1}{xyz}\)
Tính:
\(D=\dfrac{4x^2-1}{\left(x-y\right)\cdot\left(x+y\right)}+\dfrac{4y^2-1}{\left(y-z\right)\cdot\left(y-x\right)}+\dfrac{4z^2-1}{\left(z-x\right)\cdot\left(z-y\right)}\)
\(\dfrac{1}{x+3}+\dfrac{8-x}{4x^2+8x}\)
\(\dfrac{3-2x}{\left(x-5\right)\left(x+2\right)}+\dfrac{1}{x+5}\)
