Theory

Substitute variables

To evaluate a function or an algebraic expression containing variables, values are substituted for the variables. For example, the algebraic expression $2a+3b$ can be evaluated for $a={\color{#0000FF}{4}}$ and $b={\color{#009600}{1}}.$ $2\cdot{\color{#0000FF}{4}}+3\cdot{\color{#009600}{1}}$