Tính

\(\sqrt{15x^2-8x\sqrt{15}+16}\) tại x=\(\sqrt{15}\)

Rút gọn

\(\dfrac{\sqrt{15}-\sqrt{12}}{\sqrt{5}-2}\) - \(\dfrac{6+2\sqrt{6}}{\sqrt{3}+\sqrt{2}}\)

help :(

Mark the letter A, B, C or D on your answer sheet to indicate the word(s) OPPOSITE in meaning to the underlined word(s) in each of the following questions.

Population growth rates vary among regions and even among countries within the same region.

A. restrain 

B. stay unchanged          

C. remain unstable          

D. fluctuate