The equation is 

According to subtraction property of equality: If a = b then a – c = b – c.

     (Subtract 8 from each side)

                  (Additive inverse property; 8 – 8 = 0)

                      (Add:  – 7 – 8 = – 15)

Verify:

To check the solution, substitute in original equation.           

                               (Subtract: )

Compare the values, the equation is true. The solution is.

The solution is.