Ineed to put these nine cards into three groups according to similarities i but i don't see any similarities!

What is the product of the radical expression. (7-2square root) (8+2 square root)

Noor brought 21 sheets of stickers. she gave 1/3 of a sheet to each of the 45 students at recess. she wants to give teachers 1 1/2 sheets each.

What is the value of n in the equation -1/2(2n+4)+6=-9+4(2n+1)