Inequality - A comparison of two values or expressions.For example, 10x Equation - A statement heralding the equality of two expressions.For example, 4x = 8 is one equation conversely, 10x > 20 is an inequality.

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Operating through Inequalities: multiply & Dividing


Performing multiplication or department with an inequality is practically identical to multiply or separating parts of traditional equations (with one exception, spanned below).

Consider the following examples:


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The Exception: an adverse Numbers

There is one really important exception to the rule that multiplying or splitting an inequality is the very same as multiplying or splitting an equation.

Whenever you multiply or divide an inequality through a negative number, you have to flip the inequality sign.

In the adhering to example, an alert how the sign once the inequality is divided by -2


In the complying with example, notification how the authorize becomes a > sign once the inequality is divided by -2


-2x + 15 3-2x + 15 - 15 3 - 15-2x -12x > 6
Warning: Caution as soon as Multiplying or dividing Variables

One really important implication of this rule is: you cannot divide by an unknown (i.e., a variable) uneven you room sure that its sign because you do not know whether you must flip the authorize of the inequality. There space plenty the instances wherein you will recognize the sign of a variable and also as a result, you can multiply or divide and also know for sure whether you have to flip the inequality sign. However, girlfriend must constantly ask you yourself whether you know for certain the sign of the variable prior to dividing or multiplying when taking care of an inequality.


If 2x5y 10y, what is the variety of potential worths for x?You cannot divide by y or 5y because you execute not understand whether y is an unfavorable or confident and, together such, you do not know whether to flip the inequality.

Multiple Inequalities

Just together it is feasible to settle two coincided equations, so the is feasible to settle two inequalities (or three, or four, etc.). In fixing multiple simultaneously inequalities making use of multiplication or division, the most important component is to resolve each inequality separately and also then incorporate them.


If 2x 150, what is the selection of possible values for x?1.) solve each inequality alone.2x x -5x x > 2 15x 150x 102.) integrate each inequality and also find the overlap (i.e., the locations where every inequality is satisfied--this area is the solution).x x > 2x 10The area of overlap--i.e., the solution to the set of inequalities--is where x 2

For many students, the above collection of inequalities can ideal be understood graphically. The systems to the set of inequalities is the overlapping graphical area.

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