Question

Rut gon

a) ( 2- \(\frac{a-3.\sqrt{a}}{\sqrt{a}-3}\)) . ( 2- \(\frac{5.\sqrt{a}+\sqrt{a}.b}{\sqrt{b}-5}\))

b) \(\frac{9-a}{\sqrt{a}+3}\)- \(\frac{9-6.\sqrt{a}+a}{\sqrt{a}-3}\)- 6

Answer 1

a) \(\left(2-\frac{a-3.\sqrt{a}}{\sqrt{a}-3}\right).\left(2-\frac{5.\sqrt{a}+\sqrt{a}.b}{\sqrt{b}-5}\right)\)

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

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

=4-a ( Bạn xem lại đề bài giúp mình )

b)\(\frac{9-a}{\sqrt{a}+3}-\frac{9-6\sqrt{a}+a}{\sqrt{a}-3}\) -6

=\(\frac{\left(3-\sqrt{a}\right)\left(3+\sqrt{a}\right)}{\sqrt{a}+3}+\frac{\left(3-\sqrt{a}\right)^2}{3-\sqrt{a}}-6\)

=\(3-\sqrt{a}+3-\sqrt{a}-6\)

=-2\(\sqrt{a}\)