Answer:
see below
Step-by-step explanation:
Let f = number of friends
all but one friend got 6 pieces and 1 friend got 2 for a total of 50 pieces
6(f-1) + 2 = 50
Subtract 2 from each side
6(f-1) +2-2 = 50-2
6(f-1) = 48
Divide by 6
6(f-1)/6 = 48/6
f-1 = 8
Add 1 to each side
f-1+1=8+1
f=9
Jack has 9 friends at the party
With Jack and his mom, there are 11 people