Help with this math homework

Answer: Ok for the first two they are true.
Step-by-step explanation: So how you would do this is simple, so for # 2 2x-5=11 (x) represents a number and you have to find it. So For this one put an eight in the x's place and that makes 2(8)-5=11 so when you see 2x that mean 2 times what ever x is. so 2x8=16, 16-5 =11.