simplify (-3v(24))(5v(20))

Question

a. 15√(480)
b. -15√(480)
c. -60√(30)
d. -240√(30)

Answer 1

To multiply radical expressions, remember to multiply the coefficients together and the radicals together.

(-3√(24))(5√(20)) = (-3)(5) × √((24)(20)) = -15√(480)

You might be inclined to pick choice B now, but remember that you can simplify the radical.

480 = 16 × 30     ->     We want to use these two numbers because 16 is a perfect square.

-15√(480) = -15√(16)(30) = -15√(16)√(30) = -15(4)√(30) = -60√(30)     choice C

Answer 2

(-3√(24))(5√(20))

= -15√(24*20), cummutative property of multiplication

= -60√30, since 24*20 = 4^2 * 30, and 4*15 = 60

Answer: c