a: Sai vì -2x(x+1)<>2x(x-1)
b: Sai vì (1-x)(x+1)<>(1+x)(x-1)
c: Đúng vì (x-4)(1-x)=(4-x)(x-1)
a: Sai vì -2x(x+1)<>2x(x-1)
b: Sai vì (1-x)(x+1)<>(1+x)(x-1)
c: Đúng vì (x-4)(1-x)=(4-x)(x-1)
1 xét xem các biến đổi sau đúng hay sai và giải thích
a) \(-\dfrac{3}{x-4}=\dfrac{2x}{x+1}\)
b) \(\dfrac{1-x}{1+x}=\dfrac{x-1}{x+1}\)
c)\(\dfrac{x-4}{x-1}=\dfrac{4-x}{1-x}\)
d) \(\dfrac{x-4}{x-1}-\dfrac{3x}{1-x}=\dfrac{x-4}{x-1}+\dfrac{3x}{x-1}=\dfrac{4x-4}{x-1}=4\)
Tính phép tinh sau :
a) \(x-1-\dfrac{x^2-4}{x+1}\)
b) \(\dfrac{3x-1}{6x+2}-\dfrac{3x+1}{2-6x}-\dfrac{6x}{9x^2-1}\)
c)\(\dfrac{x}{x^2-2x}-\dfrac{x^2+4x}{x^3-4x}-\dfrac{2}{x^2+2x}\)
d) \(\dfrac{2x^2+1}{x^3+1}-\dfrac{x-1}{x^2-x-1}-\dfrac{1}{x+1}\)
Tính:
a) \(\dfrac{9-3x}{x^2+3x+4}-\dfrac{3x-23}{\left(1-x\right)\left(x+4\right)}\)
b) \(\dfrac{4-x}{x^3+2x}-\dfrac{x+5}{x^3-x^2+2x-2}\)
c)\(\dfrac{x^2-3}{x^3+2x^2-x-2}-\dfrac{x}{2-x-x}\)
1) thực hiện phép tính
a) \(\dfrac{x-3}{4x+4}-\dfrac{x-1}{6x-30}\)
b) \(\dfrac{1}{x-5x^2}-\dfrac{25x-15}{25x^2-1}\)
c) \(\dfrac{x+9y}{x^2-9y^2}-\dfrac{3y}{x^2-3xy}\)
d) \(\dfrac{3x+1}{\left(x-1\right)^2}-\dfrac{1}{x+1}-\dfrac{x+3}{1-x^2}\)
e) \(\dfrac{3\left(x-2\right)}{x^2-2x+1}-\dfrac{6}{x^2-1}-\dfrac{3x-2}{1-x^2}\)
Thực hiện các phép tính sau :
a) \(\dfrac{x^3-x^2+x-1}{x^2-4}-\dfrac{x-2}{x^2+3x+2}-\dfrac{3x}{x^2-x-2}-\dfrac{2x+5}{\left(x+1\right)\left(4-x^2\right)}\)
b) \(\dfrac{19^2-30x+9}{2x^3+54}-\dfrac{x^3-3}{2^2+6x}-\dfrac{3x^2}{2x^2-6x+18}\)
Thực hiện phép trừ :
\(\dfrac{2x}{x-1}-\dfrac{x}{x-1}-\dfrac{1}{x-1}\)
Cách thực hiện nào sau đây sai ?
(A) \(\dfrac{2x}{x-1}-\dfrac{x}{x-1}-\dfrac{1}{x-1}=\left(\dfrac{2x}{x-1}-\dfrac{x}{x-1}\right)-\dfrac{1}{x-1}=......................\)
(B) \(\dfrac{2x}{x-1}-\dfrac{x}{x-1}-\dfrac{1}{x-1}=\dfrac{2x}{x-1}-\left(\dfrac{x}{x-1}-\dfrac{1}{x-1}=..............\right)\)
(C) \(\dfrac{2x}{x-1}-\dfrac{x}{x-1}-\dfrac{1}{x-1}=\dfrac{2x}{x-1}-\left(\dfrac{x}{x-1}+\dfrac{1}{x-1}\right)=........\)
(D) \(\dfrac{2x}{x-1}-\dfrac{x}{x-1}-\dfrac{1}{x-1}=\dfrac{2x}{x-1}+\dfrac{-x}{x-1}+\dfrac{-1}{x-1}=.........\)
a)\(\dfrac{3}{2y+4}-\dfrac{1}{3y+6}\)
b)\(\dfrac{1}{2x-3}-\dfrac{1}{2x+3}\)
c)\(\dfrac{1}{xy-x^2}-\dfrac{1}{y^2-xy}\)
d)\(\dfrac{x+1}{x+4}-\dfrac{x^2-4}{x^2-16}\)
1) tính
a) \(\dfrac{2}{x^2+2x}+\dfrac{2}{x^2+6x+8}+\dfrac{2}{x^2+10x+24}+\dfrac{2}{x^2+14x+48}\)
b) \(\dfrac{1}{1-x}+\dfrac{1}{1+x}+\dfrac{2}{1+x^2}+\dfrac{4}{1+x^4}+\dfrac{8}{1+x^8}+\dfrac{16}{1+x^{16}}\)
Bài 1: Thực hiện phép chia:
a) \(\dfrac{5}{x}+\dfrac{x}{x+6}-\dfrac{30}{x^2+6x}\) với x ≠ -6 và x ≠ 0
b) \(\dfrac{3x+1}{\left(x-1\right)^2}-\dfrac{1}{x+1}+\dfrac{x+3}{1-x^2}\) với x ≠ \(\pm\)1
c) \(\dfrac{3x^2+2x+1}{x^3-1}-\dfrac{1-x}{x^2+x+1}-\dfrac{2}{x-1}\) với x ≠ 1