Quick

1.which answer is equal to 2√-28 ?
a. -4√7
b. 4i√7
c. 4√7i
d. -4i√7

2. which answer is the solution to √2x-7 - √x = 1 ?
a. 4 only
b. 4 and 16
c. no solution
d. 16 only

which answer is equal to 2√-28?
basically, this question wants you to simplify 2√-28. find a perfect square that you can pull out of -28: -4 works just fine.

2√-28 = 2√(-4 · 7)i ... take the √-4 out. the root of -4 is 2i
2(2i)√7... multiply 2*2i
4i√7 is your result. 

which answer is the solution to √2x-7 - √x = 1 ?
i've tried, like, every method i know of for this problem and for some reason my answer keeps getting messed up. i entered it into my calculator and got x = 16, so i assume that's your answer, but i'm sorry i couldn't show you any work for it.