Question

Rút gọn các biểu thức sau :

a) M=x²−2x√2+2x²−2  với x≠±√2

b) N=x+√5x²+2x√5+5  với x≠−√5

 

 

Answer 1

\(a,M=\dfrac{\left(x-\sqrt{2}\right)^2}{\left(x-\sqrt{2}\right)\left(x+\sqrt{2}\right)}=\dfrac{x-\sqrt{2}}{x+\sqrt{2}}\\ b,N=\dfrac{x+\sqrt{5}}{\left(x+\sqrt{5}\right)^2}=\dfrac{1}{x+\sqrt{5}}\)

Answer 2

\(N=\dfrac{x+\sqrt{5}}{x^2+2x\sqrt{5}+5}=\dfrac{1}{x+\sqrt{5}}\)