a,
Đkxđ: [tex]x\neq 2,x\neq -2, x\neq 0, x\neq 3 [/tex]
[tex]A= (\frac{4x}{2+x}+\frac{8x^{2}}{4-x^{2}})\div (\frac{x-1}{x^{2}-2x}-\frac{2}{x})[/tex]
[tex]A=\frac{4x(x-2)-8x^{2}}{(x+2)(x-2)}\div \frac{x-1-2(x-2)}{x(x-2)}[/tex]
[tex]A=\frac{4x^{2}-8x-8x^{2}}{(x+2)(x-2)}\div \frac{x-1-2x+4}{x(x-2)}[/tex]
[tex]A=\frac{-4x^{2}-8x}{(x-2)(x+2)}\times \frac{x(x-2)}{-x+3}[/tex]
[tex]A= \frac{-4x(x+2)}{(x-2)(x+2)}\times \frac{x(x-2)}{-x+3}[/tex]
[tex]A= \frac{-4x^{2}}{-x+3}[/tex]
b,
Với [tex]x\neq 2,x\neq -2, x\neq 0, x\neq 3 [/tex]; ta có:
[tex]\left | x-3 \right |=1[/tex]
[tex]\Leftrightarrow x-3=1[/tex] hoặc [tex]x-3=-1[/tex]
[tex]\Leftrightarrow x=4[/tex] hoặc [tex]x=2[/tex]
[tex]\Rightarrow x=4[/tex] (vì [tex]x\neq 2[/tex])
Thay [tex]x=4[/tex] vào [tex]A[/tex]; ta có:
[tex]A= \frac{-4\times 4^{2}}{-4+3}=64[/tex]
[TẶNG BẠN] TRỌN BỘ Bí kíp học tốt 08 môn
