Please help me on this will give you brainliest!!

There are 15 plates and each plate is either 7 or 12 inches diameter. which systems of equations do you use to find the number of 7 inch plates, x and 12 inch plates, y

Sandy is ordering bread rolls for her party, she wants 3/5 of the rolls to be whole wheat. what other factions can represent part of the rolls that will be whole wheat? shade the models to show your work.

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