How do you solve a combined rectangle problem

You are measuring the dimensions of the floor in your bedroom because you are planning to buy new carpet. which unit of measure is the most appropriate to use in this situation?

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

If you are trying to move an attached term across the equal sign (=), what operation would you use to move it?