Question

Cho P = \(\dfrac{(\sqrt a +\sqrt b )^2 - 4\sqrt ab}{\sqrt a -\sqrt b }\)

a) Rút gọn P

b) Tìm P khi a = 4 ; b = 1

Answer 1

sửa đề bài xíu \(4\sqrt{a}b\) =>\(4\sqrt{ab}\)

ĐKXĐ: a,b>0; a\(\ne\)b

a/ P=\(\frac{a+2\sqrt{ab}+b-4\sqrt{ab}}{\sqrt{a}-\sqrt{b}}=\frac{\left(\sqrt{a}-\sqrt{b}\right)^2}{\sqrt{a}-\sqrt{b}}=\sqrt{a}-\sqrt{b}\)

b/ P= \(\sqrt{4}-\sqrt{1}=2-1=1\)