Whats the square root of negative 8 times the square root of negative 10?

1 Answer
Sep 22, 2015

This is written as:

sqrt(-8)sqrt(-10)810

What you can do is factor out the two sqrt(-1)1 and multiply them, canceling the square root, but not changing the sign of the number under it:

sqrt(-8)sqrt(-10) = sqrt(-1)*sqrt(8)*sqrt(-1)*sqrt(10)810=18110

= -sqrt(80)=80

= -sqrt(16*5)=165

= color(blue)(-4sqrt5)=45