Question

[Sách Giáo Khoa]

Tính:

a. \(\sqrt{16}.\sqrt{25}+\sqrt{196}:\sqrt{49};\)

b. \(36:\sqrt{2.3^2.18}-\sqrt{169};\)

c. \(\sqrt{\sqrt{81}};\)

d. \(\sqrt{3^2+4^2}.\)

Answer 1

[Đức Minh]

a) \(\sqrt{16}\cdot\sqrt{25}+\sqrt{196}:\sqrt{49}\)

\(=\sqrt{16\cdot25}+\sqrt{196:49}\)

\(=20+2=22\)

b) \(36:\sqrt{2\cdot3^2\cdot18}-\sqrt{169}\)

\(=36:\sqrt{324}-\sqrt{169}\)

\(=36:18-13=2-13=-11\)

c) \(\sqrt{\sqrt{81}}\)

\(=\sqrt{9}=3\)

d) \(\sqrt{3^2+4^2}\)

\(=\sqrt{9+16}=\sqrt{25}=5\)

Answer 2

[Lưu Ngọc Hải Đông]

a) \(\sqrt{16}.\sqrt{25}+\sqrt{196}\div\sqrt{49}\)

\(=4.5+14:7\)

\(=20+2=22\)

b) \(36:\sqrt{2.3^2.18}-\sqrt{169}\)

\(=36:18-13=-11\)

c) \(\sqrt{\sqrt{81}}=\sqrt{9}=3\)

d) \(\sqrt{3^2+4^2}=\sqrt{25}=5\)