Australia
Austria
Belgium
Brazil
Canada
China
Croatia
Czech Republic
France
Germany
Hungary
Ireland
Italy
Malaysia
Mexico
Netherlands (see also Transportation in the Netherlands):
Norway
Portugal
Philippines
Serbia:
Spain
Sweden
Switzerland
Thailand
United Kingdom:
United States:
Recently closed:
... the square" is to add a constant (i.e., in this case, a quantity that does not depend on x) to the expression to the left of "=", that will make it a perfect square ...