a, \(\sqrt{1,6}.\sqrt{250}+\sqrt{19,6}:\sqrt{4,9}\)
= \(\sqrt{1,6.250}+\sqrt{19,6:4,9}\)
= \(\sqrt{16.\dfrac{1}{10}.250}+\sqrt{\dfrac{196}{10}:\dfrac{49}{10}}\)
= \(\sqrt{16.25}+\sqrt{\dfrac{196}{49}}\)
= \(\sqrt{\left(4.5\right)^2}+\sqrt{\left(\dfrac{14}{7}\right)^2}\)
= 4.5 + \(\dfrac{14}{7}\)
= 20 + 2 = 22
b, \(2\sqrt{27}+\sqrt{\left(1-\sqrt{3}\right)^2}-7\sqrt{3}\)
= \(2\sqrt{3^2.3}+\left|1-\sqrt{3}\right|-7\sqrt{3}\)
= \(2.3\sqrt{3}-\left(1-\sqrt{3}\right)-7\sqrt{3}\) (vì \(\sqrt{3}>1\) nên \(1-\sqrt{3}< 0\))
= \(6\sqrt{3}+\sqrt{3}-1-7\sqrt{3}\)
= \(\left(6+1-7\right)\sqrt{3}-1\)
= \(0\sqrt{3}-1\)
= -1
Chúc bn học tốt!
