Question

write the given expression in terms of i : √-245

a) -245 i

b) -7 i √5

c) i √-245

d) 7 i √5

Answer 1

Okay, so first things first:
i = $\sqrt{-1}$
That said, no answer that has -245 is correct.

Now we just need to solve $\sqrt{245}$
245/5=5*49
$\sqrt{5} * \sqrt{49} = 7i*\sqrt{5}$
So, that's your answer, option D.