System A: x+3y=-9 2x+y=4. System B: 3x+4y=-9 2x+y=4 1. how can we get system b from system a? Choices: A- Replace one equation with the sum/difference of both equations B- Replace only the left-hand side of one equation with the sum/ difference of the left-hand sides of both equations C- Replace one equation with a multiple of itself D- Replace one equation with a multiple of the other equation 2. Based on the previous answer, are the systems equivalent? In other words, do they have the same solution? a- yes b-no