The graph of a linear inequality in one variable is a number lineInequalities that have the same solution are called equivalent. Division of both sides of an inequality with a positive number produces an equivalent inequality. A linear equation is an equation of a straight line, written in one variable. The only power of the variable is 1. The solution set consists of all values that make the equation true. For this equation, the solution set is all real numbers because any real number substituted for x will make the equation true.