The technique is known as algebra.
Chat with our AI personalities
You isolate variables in math because the point of an equation is to solve for the variables. By isolating the variables you have learned what that variable stands for and thus solved the equation.
"Solve an equation" means "find out, for which values of the variable or variables is the equation true".
5r2=80
You cannot solve one linear equation in two unknown variables.
To solve for 2 unknown variables you need 2 independent equations. You have only 1.