\(\frac{4x^2-16}{x^2+2x}=\frac{A}{x}\)\(\Leftrightarrow\frac{4\left(x^2-4\right)}{x\left(x+2\right)}=\frac{A}{x}\)

\(\Leftrightarrow\frac{4\left(x+2\right)\left(x-2\right)}{x\left(x+2\right)}=\frac{A}{x}\)\(\Leftrightarrow\frac{4\left(x-2\right)}{x}=\frac{A}{x}\)

\(\Leftrightarrow4\left(x-2\right)=A\Leftrightarrow A=4x-8\)

\(\frac{x}{x^2-2x}=\frac{B}{4x^2-16}\Leftrightarrow\frac{x}{x\left(x-2\right)}=\frac{B}{\left(2x+4\right)\left(2x-4\right)}\)

\(\Leftrightarrow x\left(2x+4\right)\left(2x-4\right)=x\left(x-2\right).B\)

\(\Rightarrow B=\frac{x.\left[2\left(x+2\right)\right].\left[2\left(x-2\right)\right]}{x\left(x-2\right)}=\frac{x.2\left(x+2\right).2\left(x-2\right)}{x\left(x-2\right)}\)

\(B=\frac{x.4\left(x+2\right)\left(x-2\right)}{x\left(x-2\right)}=4\left(x+2\right)\)

\(\frac{x}{x^2-2x}=\frac{B}{4x^2-16}\)

\(\frac{x}{x\left(x-2\right)}=\frac{B}{4.\left(x^2-4\right)}\)

\(\frac{1}{x-2}=\frac{B}{4.\left(x^2-4\right)}\)

\(\Rightarrow B.\left(x-2\right)=4.\left(x-2\right)\left(x+2\right)\)

\(B=4.\left(x+2\right)\)

\(B=4x+8\)

\(\frac{4x^2}{x^2+2x}=\frac{A}{x}\)\(\Rightarrow\frac{x\cdot4x}{x\left(x+2\right)}=\frac{A}{x}\)

\(\Rightarrow\frac{4x}{x+2}=\frac{A}{x}\Rightarrow4x^2=A\left(x+2\right)\)\(\Rightarrow A=\frac{4x^2}{x+2}\)

A=\(\frac{4x^2}{x+2}\)

đề đúng này hả /hoi-dap/question/139801.html nick kia giải r` kia

ko ai rảnh để trả lời đâu

\(B-2x^2y^3z^2+\frac{2}{3}y^4-\frac{1}{5}x^4y^3=A\)

\(\Rightarrow B=A+2x^2y^3-\frac{2}{3}y^4+\frac{1}{5}x^4y^3\)

\(\Rightarrow B=-4x^5y^3+x^4y^3\cdot3x^2y^3z^2+4x^5y^3+x^2y^3z^2-2y^4+2x^2y^3z^2-\frac{2}{3}y^4+\frac{1}{5}x^4y^3\)

\(=\left(-4x^5y^3+4x^5y^3\right)+\left(x^2y^3z^2+2x^2y^3z^2\right)+x^4y^3\cdot3x^2y^3z^2-\left(2y^4+\frac{2}{3}y^4\right)-\frac{1}{5}x^4y^3\)

\(=3x^2y^3z^2+x^4y^3\cdot3x^2y^3z^2-\frac{8}{6}y^4-\frac{1}{5}x^4y^3\)

Ngu vcl

\(\frac{4x^2-16}{x^2+2x}=\frac{A}{x}\Rightarrow\frac{4.\left(x^2-4\right)}{x.\left(x+2\right)}=\frac{A}{x}\Rightarrow\frac{4.\left(x+2\right)\left(x-2\right)}{x.\left(x+2\right)}=\frac{A}{x}\Rightarrow\frac{4.\left(x-2\right)}{x}=\frac{A}{x}\Rightarrow A=\frac{4x\left(x-2\right)}{x}=4\left(x-2\right)=4x-8\)

a) Theo mình thì chỉ min thôi nhé!

\(A=\frac{8x^2-1}{4x^2+1}+1+11=\frac{12x^2}{4x^2+1}+11\ge11\)

b)Bạn rút gọn lại giùm mìn, lười quy đồng lắm:(

4(x-2)