To get it into standard you need to simplify
6y - 12 = -3x add 12 to both sides
6y = -3x + 12 add 3x to both sides
3x + 6y = 12
And that is in standard which is A + B = C
The sum of n terms of a geometric series is given by

Substituting the given numbers, you have

There are 6 terms in the series.
Well the average would change from 85 to 85.4
Answer:
Andrew is driving at a faster speed and they both started at the same place.
You just multiply the 2 numbers!