What is the answer to the bottom not the one that i have the answer on though

Which of the following represents a number squared is equal to twenty more than nine times that number ? a) x squared = 9x + 20 b) x squared = 20x + 9 c) x squared > 9 + 20x d) x squared = 9 + x + 20

When x = 3 and y = 5, by how much does the value of 3x2 – 2y exceed the value of 2x2 – 3y ?

Suppose that sahil knows that 45 people with ages of 18 to 29 voted. without using a calculator, he quickly says then 135 people with ages of 30to 49 voted. is he correct? how might sohil have come up with his answer so quickly?