Question

write the expression in the form bi, where b is the real number

squareroot-16

squareroot-25

squareroot-3

squareroot-5

Answer 1

what is 4i squared? 5i?

Answer 2

√-16
= √-1√16
= 4i

now you do the others the same way.

Answer 3

sqrt(-16)=sqrt(-1)sqrt(16)=i sqrt(16)=4i
sqrt(-25)=sqrt(-1)sqrt(25)=i sqrt(25)=5i

I think you can see it now. Just remember i=sqrt(-1). And don't forget your properties of sq-roots.