Question

căn 8 -2cawn 32 +3cawn 50

1 phần 3+cawn2 -1 phần 3-cawn2 

(căn 12 + căn 27 - căn 108 )nhân 2cawn3 

 

Answer 1

\(\sqrt{8}-2\sqrt{32}+3\sqrt{50}\)

= \(\sqrt{2.2^2}-2\sqrt{4^2.2}+3\sqrt{5^2.2}\)

= \(2\sqrt{2}-8\sqrt{2}+15\sqrt{2}\)

= \(9\sqrt{2}\)

 

Answer 2

\(\dfrac{1}{3}+\sqrt{2}-\dfrac{1}{3}-\sqrt{2}\)

= \(\left(\dfrac{1}{3}-\dfrac{1}{3}\right)\left(\sqrt{2}-\sqrt{2}\right)\)

= 0

Answer 3

\(\left(\sqrt{12}+\sqrt{27}-\sqrt{108}\right).2\sqrt{3}\)

= \(\left(2\sqrt{3}+3\sqrt{3}-6\sqrt{3}\right).2\sqrt{3}\)

= \(-\sqrt{3}.2\sqrt{3}\)

= \(-6\)

Answer 4

b:Ta có: \(\dfrac{1}{3+\sqrt{2}}-\dfrac{1}{3-\sqrt{2}}\)

\(=\dfrac{3-\sqrt{2}-3-\sqrt{2}}{7}\)

\(=\dfrac{-2\sqrt{2}}{7}\)

Answer 5

a: Ta có: \(\sqrt{8}-2\sqrt{32}+3\sqrt{50}\)

\(=2\sqrt{2}-2\cdot4\sqrt{2}+3\cdot5\sqrt{2}\)

\(=9\sqrt{2}\)

c: Ta có: \(\left(\sqrt{12}+\sqrt{27}-\sqrt{108}\right)\cdot2\sqrt{3}\)

\(=\left(2\sqrt{3}+3\sqrt{3}-6\sqrt{3}\right)\cdot2\sqrt{3}\)

=-6