9, 2, -5... so is going down by 7 each time, meaning the "common difference" is -7.
On the right side, there are
• 2•2 = 4 atoms of Nb
• 2•5 = 10 atoms of O
so among the reactants on the left, the reaction is balanced as
4 Nb + 5 O₂ → 2 Nb₂O₅
Answer:
2 gallons
Step-by-step explanation:
there are 16 cups in a gallon. if you have 30 cups for people, do 
which you cant have 0.875 gallons of juice, so you need to round it to two gallons.
Let the distance be x miles
Time = Distance / speed
Time taken by Mike to go to his friend's house = x / 40 hours
Time taken by him to return = x / 45 hours
Total time = x / 40 + x / 45 = 4 hours
= 9x + 8x = 1440 miles
17x = 1440
= x = 1440 ÷ 7
= x = 84.706
Time taken to return home = 84.706 /45= 1.882 hours .
Therefore , Mike took 1.882 hours to reach home .
