mn ơi giúp t vs ạ

Đáp án:

$\begin{array}{l}
1a)\sqrt {25.144} \\
 = \sqrt {{5^2}{{.12}^2}} \\
 = 5.12\\
 = 60\\
b)\sqrt {52} .\sqrt {13} \\
 = \sqrt {52.13} \\
 = \sqrt {4.13.13} \\
 = \sqrt {{2^2}{{.13}^2}} \\
 = 2.13\\
 = 26\\
1B\\
a)\sqrt {45.80} \\
 = \sqrt {9.5.16.5} \\
 = \sqrt {{3^2}{{.5}^2}{{.4}^2}} \\
 = 3.5.4\\
 = 60\\
b)\sqrt 7 .\sqrt {28} \\
 = \sqrt {7.28} \\
 = \sqrt {7.7.4} \\
 = \sqrt {{7^2}{{.2}^2}} \\
 = 7.2\\
 = 14\\
2A\\
a)\sqrt {1\dfrac{9}{{16}}} \\
 = \sqrt {\dfrac{{25}}{{16}}} \\
 = \sqrt {{{\left( {\dfrac{5}{4}} \right)}^2}} \\
 = \dfrac{5}{4}\\
b)\dfrac{{\sqrt {12,5} }}{{\sqrt {0,5} }}\\
 = \sqrt {\dfrac{{12,5}}{{0,5}}} \\
 = \sqrt {25} \\
 = \sqrt {{5^2}} \\
 = 5
\end{array}$