When must a system of linear equations be solved algebraically, not graphically? whenever the solution to a system does not have coordinates, it can be difficult or impossible to find the precise answer through graphing.

Sometimes solving a system of linear equations using graphs or graphically is not useful.  There are many reasons behind this, it could be dealing with numbers that are very big or tiny or those that have to be precise to few decimal places which is hard to graph. Since, it can be difficult or impossible to find the precise answer through graphing.

These are the multiples of 15 but what you are probably asking or what are the factors of 15