Now I kind of have an idea of what im doing(by this, I mean I can take an educated guess as to what the answer is and be correct sometimes), but im looking for an explanation more than anything

I have this problem: (x + 1)^2 = -9

I then put a radical sign over the -9, get rid of the exponent and end up with

x + 1 = (assume a radical sign) -9

the -9 turns into 3i, because the SR of 9 is 3, and the negative factors out and makes an imaginary number

so far so good, until I see the answer is -1 plus or minus 3i

Unfortunately my book isnt very good, I was wondering if someone can help me finish the problem from where I left off.