Question

rút gọn biểu thức

5\(\sqrt{x}\)-\(\dfrac{\left(x+10\sqrt{x}+25\right)\left(\sqrt{x}-5\right)}{x-25}\)

Answer 1

Với `x >= 0,x \ne 25` có:

`5\sqrt{x}-[(x+10\sqrt{x}+25)(\sqrt{x}-5)]/[x-25]`

`=5\sqrt{x}-[(\sqrt{x}+5)^2(\sqrt{x}-5)]/[(\sqrt{x}+5)(\sqrt{x}+5)]`

`=5\sqrt{x}-\sqrt{x}-5=4\sqrt{x}-5`

Answer 2

\(5\sqrt{x}-\dfrac{\left(x+10\sqrt{x}+25\right)\left(\sqrt{x}-5\right)}{x-25}\)

\(=5\sqrt{x}-\dfrac{\left(\sqrt{x}+5\right)^2\left(\sqrt{x}-5\right)}{x-25}\)

\(=5\sqrt{x}-\dfrac{\left(x-25\right)\left(\sqrt{x}+5\right)}{x-25}\)

\(5\sqrt{x}-\sqrt{x}-5\)

\(=4\sqrt{x}-5\)