What is the missing number in the list of perfect squares 1,4,9,16,25,36,49,_,81,100,121,144

How many $20 bills do you need to have to make $280

To solve the system of equations below, grace isolated the variable y in the first equation and then substituted into the second equation. what was the resulting equation? 3y=12x x^2/4+y^2/9=1

If a line is defined by the equation y = 5x + 2, what is the slope?