What properties are being used in these expressions? 1. (3x+7)+(2x+8)=3x+7+2x+8
2. 3x+7+2x+8=3x+2x+7+8
3. 3x+2x+7+8=(3x+2x)+(7+8)

Just tell me how to set up the equation.

Which one ? is the answer and how to find this answer

Brainliest ! which of the coordinates are not of th vertices of the feasible region for the system of inequalities y≤4,,x≤5,x+y> 6 a(2,4) b(0,6) c(5,4) d(5,1)