First you divide 12 by 100 to get the percent into a decimal which is .12 then you multiply 552.50 by .12, that is how much they have raised so far. Then you subtract that number from 552.50 and divide by 7
So you want to start to factor so you get (x²+2)(x²-7) = 0. Now set each () to 0, so you get (x²+2) = 0 and (x²-7)=0. The first ends with +√2i and -√2i, the second ends with +√7 and -√7