When we solve the very first equation, we get:
-5 x - 10 = - 5 x - 10
which is an identity (same expression on the left than on the right of the equal sign) , meaning that whatever x-value we use the two expressions will be equal and therefore render the equation TRUE. for all possible values of "x". So this equation gives INFINITE number of solutions.
Equation A is the equation we were looking for.