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.
To solve a pair of simultaneous equations, first eliminate one of the letter terms and find the value of the remaining letter. You can then substitute this value into the original equations to find the value of the other letter term. A common way of solving simultaneous equations is by equating the coefficients. This means getting the number in front of a letter term the same by multiplying one of both of the equations.