Question 1119863
10,000 with on child.
3,000 more for an additional child.


if each child costs 3000, , then you can make a straight line equation.


it will be y = 7000  + 3000 * x, where x is the number of children.


0 children would cost 7000, which is the presumably the cost for the couple.
1 child would raise it by 3000.
2 children would raise it by 6000.
etc....


the relation changes by 3000 for each additional child.