To write a system of equations, it usually equals y=mx+b. Since Danny and Avery both earn the set monthly allowance of 20 and 18 dollars respectively, those numbers go on the variable b since it's a set amount and they start off with that amount of money if they weren't nice to their mom at all.
Since we are trying to find the overall amount of money, let y=total money a child earns every month and x=how many times the child is nice to their mother.
The extra .75 cents Danny earns go under the variable m because it is dependent on how many times he is nice to his mom. Along with Avery.
