Posted by Ava on .
Use rational exponents to write 4suare root 5 * 2 sqaure root 8
Please help.. I can't find the square root button

Rational exponents 
drwls,
The subject is rational (fractional) exponents, not radical.
4sqrt5 * 2 sqrt8 = 8 sqrt40
= 8 sqrt(4*10) = 16 sqrt10