Answer:
Each will receive
of the cake.
Step-by-step explanation:
Let the amount of cake = c
Lisa, Juan and Isaac are the persons who are sharing half of a cake equally.
Number of persons = 3
Part of the cake shared = 
Fraction of the cake shared by each = 
=
= 
Therefore, fraction of total cake shared by each member will be
of the total amount of cake.
Using the distributive property, you can distribute the 7 to y and -4. In other words, multiply the number outside of the parenthesis by each of the numbers in the parentheis.
7*y+7*-4
=7y-28
:)