# Solving Linear Equations

##### 1. Introduction
[justify]These equations are know as [b]linear[/b], because the [b]monomial literal part[/b] doesn't have an exponent (for example, [i]3x[/i] can be part of a linear equation, but [i]3x[sup]2[/sup][/i] can't because it's quadratic), so represented in a graph appear as a line. This fact assures us that if there is a solution, there can only be one solution (except in special cases were there are infinite solutions).[br][br]We say [i][b]if there is a solution[/b][/i] because sometimes equations don't have solutions. For example, the equation [i]x = x + 1[/i] (which means a number equals the consecutive number) doesn't have a solution, because this is never true. In reality, this equation is reduced to [i]1 = 0[/i], which is impossible.[/justify]
##### 2. Tips for solving the equations
[justify][/justify][list][br][*] If we obtain an [b]impossible equality[/b], there is no solution, like [i]1 = 0[/i].[/*][/list][list][*] If we obtain an [b]equality that is always true[/b], whatever value gives a solution, then the solution is all real numbers. For example, if we obtain [i]0 = 0[/i].[br][/*][/list][list][*] When there are [b]denominators[/b] and we want to avoid them, we multiply the full equation by the same [b]least common multiple[/b] of the denominators. This way when we simplify, they disappear.[br][/*][/list][list][*][b]To remove the parenthesis[/b], we multiply the coefficient in front of it by all the elements it contains. This coefficient can be a negative sign (like –1, the content changes sign), a positive sign (like +1, the content doesn't change) or a positive or negative number or fractions (this number multiplies everything in the parentheses, changing the signs if its negative).[br][/*][/list][list][*] When we have a [b]nested parenthesis[/b], a parenthesis inside another parenthesis, we begging removing from outside to the inside. First, we remove the exterior parenthesis (multiplying it's content by the coefficients) and afterwards, we remove the rest the same way: from the most exterior to the interior.[br][br]Realistically, there isn't any need to follow an order when removing the parenthesis, but it's recommended to follow one when we are learning.[br][/*][/list]
##### 3. Resolved Linear Equations
Link: [url=https://www.matesfacil.com/english/secondary/linear-equations-solved.html][b]Resolved Linear Equations step by step[/b]: with fractions, parenthesis, negative signs... [br][/url]Link: [url=https://www.matesfacil.com/english/secondary/resolved-problems-linear-equations.html][b]Resolved Problems[/b] of Linear Equations[/url]