Question

Rút gọn \(A=\frac{x\left|x-2\right|}{x^2+8x-20}\)

Answer 1

x² + 8x - 20 = x² + 10x - 2x - 20 = x(x+10) - 2(x+10) = (x - 2)(x+ 10)

|x - 2| = x - 2 nếu x > 2; |x - 2| = -(x - 2) = - x + 2 nếu x < 2

Vậy A = \(\frac{x\left(x-2\right)}{\left(x-2\right)\left(x+10\right)}=\frac{x}{x+10}\) nếu x > 2

A = \(\frac{-x\left(x-2\right)}{\left(x-2\right)\left(x+10\right)}=\frac{-x}{x+10}\) nếu x < 2

 

Answer 2

A=(x/x-2/)/x^2+8x-20=(x/x-2/)/(x-2).(x+10)

TH1:x>=2

A=x.(x-2)/(x-2).(x+10)=x/x+10

TH2:x<2

A=(-x).(x-2)/(x-2).(x+10)=-x/x+10

Answer 3

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