Please help i do not understand how to solve this type of question Find the average rate of change of a function given its equation

Four equations are shown below. equation 1: y=2*equation 2: y=2x-5equation 3: y=x2 + 6equation 4: tdentify one linear equation and one nonlinear equation from the list. why each equation you identified is linear or nonlinear. nd one nonlinear equation from the list. state a reasonlinear equation