Câu hỏi của Mai Linh

Question

a, Thực hiện phép tính: $\dfrac{3x-8}{x-2}$ + $\dfrac{5-x}{2-x}$ + $\dfrac{2x+1}{x-2}$

b, Rút gọn biểu thức: A = $\dfrac{x^2-2x+1}{x^2-1}$

Luân Đào · Accepted Answer

a.

$\dfrac{3x-8}{x-2}+\dfrac{5-x}{2-x}+\dfrac{2x+1}{x-2}$

$=\dfrac{3x-8}{x-2}-\dfrac{5-x}{x-2}+\dfrac{2x+1}{x-2}=\dfrac{3x-8-5+x+2x+1}{x-2}=\dfrac{6x-12}{x-2}=\dfrac{6\left(x-2\right)}{x-2}=6$

b.

$A=\dfrac{x^2-2x+1}{x^2-1}=\dfrac{\left(x-1\right)^2}{\left(x-1\right)\left(x+1\right)}=\dfrac{x-1}{x+1}$Câu trả lời: a.

$\dfrac{3x-8}{x-2}+\dfrac{5-x}{2-x}+\dfrac{2x+1}{x-2}$

$=\dfrac{3x-8}{x-2}-\dfrac{5-x}{x-2}+\dfrac{2x+1}{x-2}=\dfrac{3x-8-5+x+2x+1}{x-2}=\dfrac{6x-12}{x-2}=\dfrac{6\left(x-2\right)}{x-2}=6$

b.

$A=\dfrac{x^2-2x+1}{x^2-1}=\dfrac{\left(x-1\right)^2}{\left(x-1\right)\left(x+1\right)}=\dfrac{x-1}{x+1}$

Lê Ngọc Cương · Answer

a)

$\dfrac{3x-8}{x-2}+\dfrac{5-x}{2-x}+\dfrac{2x+1}{x-2}\
=\dfrac{3x-8+x-5+2x+1}{x-2}\
=\dfrac{6x-12}{x-2}\
=\dfrac{6\left(x-2\right)}{x-2}\
=6$

b)

$A=\dfrac{x^2-2x+1}{x^2-1}\
A=\dfrac{\left(x-1\right)^2}{\left(x-1\right)\left(x+1\right)}\
A=\dfrac{x-1}{x+1}$Câu trả lời: a)

$\dfrac{3x-8}{x-2}+\dfrac{5-x}{2-x}+\dfrac{2x+1}{x-2}\
=\dfrac{3x-8+x-5+2x+1}{x-2}\
=\dfrac{6x-12}{x-2}\
=\dfrac{6\left(x-2\right)}{x-2}\
=6$

b)

$A=\dfrac{x^2-2x+1}{x^2-1}\
A=\dfrac{\left(x-1\right)^2}{\left(x-1\right)\left(x+1\right)}\
A=\dfrac{x-1}{x+1}$

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