A way to solve a linear system algebraically is to use the substitution method. The substitution method functions by substituting the one y-value with the other. We're going to explain this by using an example. We can substitute y in the second equation with the first equation since y = y.
Area code 970 is an area code serving most of the western and northern parts of Colorado.It covers Aspen, Vail, Durango, Grand Junction, Fort Collins, and Estes Park.rea code 970 is an area code serving most of the western and northern parts of Colorado.
The overlay will affect the following counties: Utah, Salt Lake, Weber, Davis, and Morgan. *9/21/1997: Area code 801 was split. Some of the phone numbers had to be updated to area code 435 on that date. 3/29/2009: Area code 385 was created as an overlay to area code 801. The two area codes serve the same area.