Question

Which choice is equivalent to the expression below?

√- 20
A. -20i
B. 2i √5
C. -2 √5
D. 2 √5i
E. 20i,

Answer 1

D) since

`√( - 20) = √( 4 * - 5) = 2 √( - 5) = 2 √(5 * ( - 1)) = 2 \ √(5) i`

Answer 2

B. 2i √5. To simplify √- 20 , it becomes √(-2)*(-2)*5, then √(-2)^5*5, which then becomes 2i because you cannot find the square root of a negative number. i means √-1, so √-20 is the same as 2i√5.