The equation is .

According to division property of equality:

For any number a, b and c, If a = b then 

                   (Divide each side by 4)

                        (Cancel common terms)

w = 5                                       (Divide: )

Verify:

To check the solution, substitute w = 5 in original equation.    

  20 = 20                         (Multiply: )

Compare the values, the equation is true. The solution is w = 5.

The value of w = 5.