Which of the following would not be the result of a substitution in the following system? 2x+y=7 y-x=1 2(y+1)+y=7 7-2x-x=1 2x+x+1=7

The correct answer is: Explanation: This equation is not a result of a substitution in the given system of equations. The other equations are derived by substituting one variable in terms of the other from the original equations.