Question #b1685

2 Answers
Dec 14, 2016

#sqrt8*sqrt20#

#=sqrt(2^2*2)*sqrt(2^2*5)#

#=2sqrt2*2sqrt5#

#=4sqrt(2*5)#

#=4sqrt(10)#

Dec 14, 2016

Answer:

#4sqrt(10)#

Explanation:

Since sometimes students have trouble with exponents, another way to look at this question is to factor the number under the radical where one of the factors is a perfect square.
#sqrt(8)*sqrt(20)=sqrt(4*2)*sqrt(4*5)#
#color(white)(aaaaaaaa)=sqrt(4)sqrt(2)*sqrt(4)sqrt(5)#
#color(white)(aaaaaaaa)=2sqrt(2)*2sqrt(5)#
Then multiply the coefficients together separately and the numbers under the roots separately.
#color(white)(aaaaaaaaa)=(2)(2)sqrt(2*5)#
#color(white)(aaaaaaaaa)=4sqrt(10)#