Answer:
c=74
Explanation:
Let c represent how many contacts Joy had on her phone before she updated it.
Because Joy added 26 new contacts, we can say that c+26 is equal to her new total of 100 contacts.
c+26=100
Therefore, the equation that represents this situation is c+26=100
Now, we can use our equation to solve for c.
c+26=100
Subtract both sides by 26 to isolate c
c+26-26=100-26
c=74
Therefore, Joy had 74 contacts on her phone before she updated it.
I hope this helps!