I need help answering 1-3 and explaining what it means because I don’t understand ( you can help with more questions on there if you want but I really need help with 1-3)!!!!!!!

Answer:
So the question is asking you what of the two equations would you chose to solve for the variable. (which means what eqation is easier to solve and why)
Step-by-step explanation:
1) the first one is easier because you could multiple 2 or 5 to get 10 which is a nice number compare to 21 (the other eqaution)
2) the first one bc the second opption you would have a -7y +2 =x and thats a mouth full
3) the first one as well bc I work better with smaller numbers.