Hydrogen is the only element where the isotopes are given specific names. Common hydrogen, which has zero neutrons, is called protium. Hydrogen with one neutron is called deuterium and hydrogen with two neutrons is called tritium. See the picture at the top of the page.
The following steps can be used as a guide as you read through the examples for using the substitution method. Steps for Using the Substitution Method in order to Solve Systems of Equations. 1  Solve 1 equation for 1 variable. ( 2 Put in y = or x = form). 3  Substitute this expression into the other equation and solve for the missing variable. 4  Substitute your answer into the first equation and solve.
The first method is called the method of substitution. In this method we will solve one of the equations for one of the variables and substitute this into the other equation. This will yield one equation with one variable that we can solve. Once this is solved we substitute this value back into one of the equations to find the value of the remaining variable.