Its asking for the units being used so the answer is Inches
Answer:
<u><em>D:</em></u> Each point (or pair) in a proportional relationship must share the same difference.
Answer = 2x^2+6x+1
3x+2+2x^2+3x-1
3x+1+2x^2+3x
Now combine like terms
3x+1+2x^2+3x
6x+1+2x^2
Rearrange terms
6x+1+2x^2
2x^2+6x+1