Definition of Substitution Method. One way to solve systems of equations is by substitution. In this method, solve an equation for one variable, then substitute that solution in the other equation, and solve.
Area code 407 is found in the US state of Florida. Primarily servicing the city of Orlando (population: 921360), area code 407 covers 5 counties of Florida.Located in the Eastern time zone, area code 407 is on the same time as New York, NY. Area code 407 was brought into effect on April 16, 1988.407 was split from the parent 305 area code.rimarily servicing the city of Orlando (population: 921360), area code 407 covers 5 counties of Florida. Located in the Eastern time zone, area code 407 is on the same time as New York, NY.
Marin County, and San Francisco County. Major cities or places in California within area code 415 include: Area code 415 serves the larger communities of Novato, San Anselmo, San Francisco, and San Rafael, most of Marin County and all of San Francisco County.rea code 415 was put into service. In 1959 area code 415 was split to form area codes 408 and 707. In 1991 area code 415 was split to form area code 510.