Hi! This (and similar pages) appear to be a WalledGarden. Please read WelcomeVisitors. An equation has to have an equals sign, as in 3x + 5 = 11 . A solution to an equation is a number that can be plugged in for the variable to make a true number statement. For example, putting 2 in for x above in 3x + 5 = 11 gives 3(2) + 5 = 11 , which says 6 + 5 = 11 ; that's true! So 2 is a solution. But how to start with the equation, and get (not guess) the solution? 3x + 5 = 11 . . . our given equation - 5 - 5 . . . subtract 5 from each side to get constants on the right 3x = 6 . . . the result 3x / 3 = 6 / 3 . . . divide both sides by 3 to isolate the x x = 2 . . . the solution (same as before!) . . . . . . . . . . . . . We have solved the equation. . . . . . . . . . . . . . And we have done the CheckBySubstitution (UnitTest). The thing that makes this equation linear is that the highest power of x is x^1 (no x^2 or other powers; those are "QuadraticEquation''''''s". CategoryMath See also: QuadraticFormula, EigenValue, EigenVector, MatrixAnalysis ---- Please do NOT ConvertSpacesToTabs on this page.