Choice A can be obtained from the given system by multiplying the second equation by —1 so it is equivalent to the given system so it can be used to solve for x and y.

Choice B can be obtained from the given system by multiplying the second equation by 2 so it is equivalent to the given system so it can be used to solve for x and y.

Choice C can be obtained from the given system by multiplying both the frst equation the second equation hy 3 so it is equivalent to the given system so it can be used to solve for x and y.

Choice D cannot be obtained from the given system since only the left side of the seconds equation was multiplied by 2.

So, the correct answer is choice D.

Choice B can be obtained from the given system by multiplying the second equation by 2 so it is equivalent to the given system so it can be used to solve for x and y.

Choice C can be obtained from the given system by multiplying both the frst equation the second equation hy 3 so it is equivalent to the given system so it can be used to solve for x and y.

Choice D cannot be obtained from the given system since only the left side of the seconds equation was multiplied by 2.

So, the correct answer is choice D.