Question

Cho biểu thức : \(A=\frac{2x}{x+3}-\frac{x+1}{3-x}-\frac{3-11x}{x^2-9}\left(x\ne+-3\right)\)

   a/ Rút gọn biểu thức A.

   b/ Tìm x để  A < 2.

   c/ Tìm x nguyên để A nguyên

Answer 1

mjk giải baj này mà bận ruj huhu

Answer 2

Giao luu

\(A=\frac{2x\left(x-3\right)+\left(x+3\right)\left(x+1\right)+\left(11x-3\right)}{\left(x+3\right)\left(x-3\right)}\)

\(A=\frac{2x^2-6x+x^2+4x+3+11x-3}{\left(x+3\right)\left(x-3\right)}=\frac{3x^2+9x}{\left(x+3\right)\left(x-3\right)}=\frac{3x}{x-3}\)

b)\(A=\frac{3x}{x-3}-2< 0\Leftrightarrow\frac{3x-2x+6}{x-3}=\frac{x+6}{x-3}=1+\frac{9}{x-3}\) \(-6< x< 3\)

c) x-3=U(9)=(-9,-3,-1,1,3,9)

x=(-6,0,2,4,6,12)

Answer 3

2/3 + 2/3 = 4/3

3/4 + 5/4 = 8/4 = 2

5/6 + 7/6 = 12/6 = 2

2/9 + 1/18 = 4/18 + 1/18 = 5/18 

2/4 + 1 = 2/4 + 4/4 = 6/4 = 3/2