Inequality - A comparison of 2 values or expressions.For example, 10x Equation - A statement declaring the equality of two expressions.For example, 4x = 8 is an equation whereas 10x > 20 is one inequality.

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Operating with Inequalities: multiplying & Dividing


Performing multiplication or division with one inequality is virtually identical to multiply or splitting parts of timeless equations (with one exception, spanned below).

Consider the adhering to examples:


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The Exception: an adverse Numbers

There is one an extremely important exemption to the rule that multiply or dividing an inequality is the very same as multiply or separating an equation.

Whenever you multiply or division an inequality by a an unfavorable number, you have to flip the inequality sign.

In the following example, notice how the sign once the inequality is separated by -2


In the following example, notice how the sign becomes a > sign as soon as the inequality is split by -2


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

One very important implication of this preeminence is: you cannot division by an unknown (i.e., a variable) uneven you are sure the its sign due to the fact that you perform not recognize whether you should flip the sign of the inequality. There are 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 certain whether you must flip the inequality sign. However, friend must always ask yourself whether you recognize for certain the authorize of the variable before dividing or multiplying when managing an inequality.


If 2x5y 10y, what is the selection of potential values for x?You cannot division by y or 5y due to the fact that you do not understand whether y is an adverse or optimistic and, as such, you execute not recognize whether to upper and lower reversal the inequality.

Multiple Inequalities

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


If 2x 150, what is the variety of feasible values because that x?1.) fix each inequality alone.2x x -5x x > 2 15x 150x 102.) combine each inequality and also find the overlap (i.e., the areas where every inequality is satisfied--this area is the solution).x x > 2x 10The area of overlap--i.e., the solution to the collection of inequalities--is where x 2

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

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