Intermediate Algebra for College Students (7th Edition)

To solve an equation either in one variable let us say for $x$; we will have to find all values of $x$ that must be satisfied for the equation. Substitute the value for $x$ that satisfy the equation as a true solution. Let us take an example: $x=4$ satisfies the expression $4x=16 \implies 4(4)=16$ and $16=16$ Hence, the $4$ is a solution.