Question

[Nguyễn Khả Ái]

cho B= (2√a-9)/(a-5√a+6) - (√a+3)/(√a-2) * (2√a+1)/(3-√a)

a. tìm ĐKXĐ

b. rút gọn

Answer 1

[Nguyễn Lê Phước Thịnh]

a: ĐKXĐ: a>=0; a<>4; a<>9

b: \(B=\dfrac{2\sqrt{a}-9}{\left(\sqrt{a}-2\right)\left(\sqrt{a}-3\right)}-\dfrac{\sqrt{a}+3}{\sqrt{a}-2}+\dfrac{2\sqrt{a}+1}{3-\sqrt{x}}\)

\(=\dfrac{2\sqrt{a}-9-a+9-2a+4\sqrt{a}-\sqrt{a}+2}{\left(\sqrt{a}-3\right)\left(\sqrt{a}-2\right)}\)

\(=\dfrac{-3a+5\sqrt{a}-2}{\left(\sqrt{a}-3\right)\left(\sqrt{a}-2\right)}\)