Cho A =  $\frac{x+4}{5}.\frac{x+1}{2x}.\frac{100x}{x^2+5x+4}$. Chọn câu đúng

A. $\frac{1}{2-x}$

B. $\frac{x+2}{x-2}$

C. $\frac{x+2}{2-x}$

D. $\frac{1}{x-2}$

A. $\frac{5x^2-20y^2}{3x+6y}:\frac{5x-10y}{9x}$

B. $\frac{45x-90y}{3x+6y}:\frac{x^2-4y^2}{x^2+4xy+4y^2}$

C. $\frac{x^2-y^2}{2y}:(y-x)$

D. Cả A, B, C đều sai

A. $\frac{{(x-y)}^2}{{(x+y)}^2}:\frac{{(x-y)}^4}{{(x+y)}^3}$

B. $\frac{{(x-y)}^2}{{(x+y)}^2}:\frac{{(x-y)}^3}{{(x+y)}^3}$

C. $\frac{x-y}{{(x+y)}^2}:\frac{{(x-y)}^4}{{(x+y)}^3}$

D. $\frac{-{(x-y)}^2}{{(x+y)}^2}:\frac{{(x-y)}^4}{{(x+y)}^3}$

A. x – 2; x + 2

B. (x – 2)²; x+ 2

C. x +2; (x – 2)²

D. –(x – 2)²; x+ 2

A. x + 5

B. 2(x + 5)

C. x + 6

D. 2(x + 5)(6 – x)

A. $\frac{5(x+y)}{4(x-y)}.\frac{6(x-y)}{{(x+y)}^2}$

B. $\frac{x^2-2xy+y^2}{15x+15y}.\frac{4x^2+8xy+4y^2}{x^2-y^2}$

C. $\frac{x^{2}y+x{y}^2}{2x-2y}.\frac{15x-15y}{x^{3}y+2x^2{y}^2+x{y}^3}$

D. Cả A và C đều đúng