3 by the power of 2 times 3 by the power of 3

What number should be added to the expression x^2+3x+ in order to create a perfect square trinomial? 3/2 3 9/4 9

What statement is true? 2x^2-9x+2=-1

Your food costs are $5,500. your total food sales are $11,000. what percent of your food sales do the food costs represent?