Mark is solving the following system.
X+y+Z= 2(1)
3x+2y+z=8 (2)
4x-y-Tz= 16 (3)
Step 1: He multiplies equation (1) by 7 and adds it to equation (3). Step 2: He multiplies equation (3) by 2 and adds it to equation (2)
Which statement explains Mark's mistake?
