Write these steps: 

Think these reasons: 
Use law 1. 
a+b=b+a 
This axiom is a good start, because is has the same operation and the same order of variables. Next we replace the variables. 
Replace expression a with x. 
x+b=b+x 
Next replace b with c. 
Replace expression b with c. 
x+(c)=(c)+x 
Next we use the definition of subtraction.

Replace expression x+(c) with xc. 
xc=(c)+x 
Next we replace c with 1. 
Replace expression c with 1. 
x1=(1)+x 
Next indicate that this is the answer. 
Underline the answer. 

