Chapter 10 - Radical Expressions and Equations - 10-2 Simplifying Radicals - Practice and Problem-Solving Exercises - Page 624: 57

b. a = 45, b = 4

a. LHS: $ = \sqrt a \times \sqrt b$ $= \sqrt (a\times b)$ $= \sqrt (18\times 10)$ $= \sqrt(9 \times 2 \times 2 \times 5)$ $= \sqrt(9) \times \sqrt4 \times \sqrt 5$ $= 3 \times 2 \times \sqrt 5$ $= 6 \times \sqrt 5$ $= RHS$ Hence proved