please indicate all correct answers and explain

To convert an LP to standard form, which of the following statements is true? (Please check all correct answers.) A"s" constraint should be converted to an equality constraint by adding a slack variable s; to its left-hand side, and adding the sign restriction s;0. All decision variables must be restricted to be nonnegative For an LP with m inequality constraints and n decision variables, its standard form consists of m constraints and n decision variables For an LP with m inequality constraints and n decision variables, its standard form consists of m constraints and (m+n) decision variables. Constant terms in the objective function should be kept Az constraint should be converted to an equality constraint by subtracting an excess variable of from its left hand side, and adding the sign restriction i0. All constraints must be converted to inequalify constraints. For an LP with m inequality constraints and n decision varlables, its standard form consists of (m+n) constraints and n decision variables