Write a single variable between the absolute value symbols to mandate the use of a positive value in the evaluation of the rest of the equation. For example, in the equation 7 - | x| = 5, the values allowed as solutions to the equation are 2 and -2.
Write the expression that describes the solution to your problem. You can place the absolute value symbols around the terms that you need evaluated as a positive number. For example, the equation y = 2x^2 * (4 -- x) + 15 will result in the middle term going negative when the value of x rises above 4. By placing an absolute value around the parentheses, the term has limits placed that result in a positive value in every situation. The resulting equation would be y = 2x^2 * |4 -- x| + 15.
Write the absolute value symbols around a portion of the expression can limit the expression from going negative or from entering imaginary space. For example, plot the values of x and y on a graph where y = (sqrt |(4 -- x)|). The results of the expression as written are (1, sqrt(3)), (2, sqrt(2)), (3, sqrt(1)), (4, sqrt(0)), (5, sqrt(1)) and (6, sqrt(2)).