Substitution

On January 7th, 2014 in Mathland, we went back to middle school and learned about a concept of basic algebra called substitution. We use substitution among two problems/equations to solve out the variables in them. In reality, we can also use elimination to do the same exact thing, but there are some cases where it will be easier for one or the other. There are four total steps in substitution which includes:

1) Isolate one variable in one equation
2) Substitute the variable found in step one the OTHER equation
3) Solve
4) Back substitution to find remaining variables

We had also learned about breaking even, losing money, or making profits. When finding out which category your business will bring you, you can also use substitution to solve your equations. To find out whether you break even, you follow three steps which includes:

1) total cost = cost per unit * initial cost
2) total revenue = price per unit * number of units
3) You break even when: total cost = total revenue

The picture above shows how to figure out the variables from two equations using substitution. As seen, two solutions were found.