Question

Giup em với mng ạ. em cảm ơn.

Answer 1

a) nhân dạng liên hiệp 

<=> \(\dfrac{4\left(\sqrt{7}+3\right)}{2}-\dfrac{3\left(\sqrt{7}+2\right)}{3}\)

= 2\(\sqrt{7}+6-\sqrt{7}-2\) = \(\sqrt{7}+4\)

b) (\(\dfrac{\left(\sqrt{x}+1\right)\left(x-\sqrt{x}+1\right)}{\sqrt{x}+1}-\sqrt{x}\)).\(\dfrac{1}{\sqrt{x}\left(\sqrt{x}-1\right)}\)

<=> ( x - \(\sqrt{x}+1-\sqrt{x}\) ) . \(\dfrac{1}{\sqrt{x}\left(\sqrt{x}-1\right)}\)

<=> \(\dfrac{\left(\sqrt{x}-1\right)^2}{\sqrt{x}\left(\sqrt{x}-1\right)}\)= \(\dfrac{\sqrt{x}-1}{\sqrt{x}}\)