I don't know if I understand this question that well, but if I am right, the first digit of the question you are asking is 5, and it is in the hundreds place. If this is not what you mean, then can you put more description in this question please?
Multiply both sides of the second equation by 4. That will give you -4x in the second equation which when added to 4x of the first equation will eliminate x.
Second equation:
-x + 3y = 6
Multiply the second equation by 4 on both sides:
-4x + 12y = 26
Answer:
the answer is -3x² caused when -x divide with 3x it will became -3x²
