All you have to do is find the rest of the percentage. Percentage adds up to 100%. So you will have to add the two percentages they gave you. 27+33=60%. Now you have to take away 60 from 100. 100-60=40%.
Kara incorrectly factored 2(16x^2 + 24x + 9) she did not find the correct factors when she factored out. The correct factored expression would be 2(4x+3)^2
Because logarithms were a lot less time-consuming than other methods of finding roots. They were also more accurate in the sense that it was harder to make a mistake.