The number of solutions of the equation x + 0y - 4 = 0 is:

As the given equation is in two variables x and y and the coefficient of y is 0, solutions of this equation are as follows: (x, y) = (4, 0), (4, 1), (4, 2), …… (4, r) where r is any real number. 

You can see that the solution only has to satisfy the value of x and it is true for any real value of y. 

Therefore, the given equation has infinite solutions.