document.write( "Question 72886This question is from textbook Intermediate Algebra
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document.write( ": how do you solve and graph inequality # 24
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document.write( "-x-2y>4 \n" );
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Algebra.Com's Answer #52144 by bucky(2189)![]() ![]() ![]() You can put this solution on YOUR website! \n" ); document.write( ". \n" ); document.write( "First solve this inequality for y. \n" ); document.write( ". \n" ); document.write( "Use the same method as you would use in solving an equation ... (for the time being you \n" ); document.write( "can sort of imagine that the > sign is an equal sign). \n" ); document.write( ". \n" ); document.write( "Begin by adding x to both sides to remove the -x from the left side. When you do that the \n" ); document.write( "inequality becomes: \n" ); document.write( ". \n" ); document.write( " \n" ); document.write( ". \n" ); document.write( "Now to solve for y you divide both sides by -2. This results in: \n" ); document.write( ". \n" ); document.write( " \n" ); document.write( ". \n" ); document.write( "At this point we have to take care of another inequality rule. This rule says that whenever \n" ); document.write( "you divide or multiply by a negative number you also need to reverse the direction of \n" ); document.write( "the inequality sign. We divided by negative 2, but we have not reversed the direction \n" ); document.write( "of the inequality sign. So let's do that before we forget it. The inequality becomes: \n" ); document.write( ". \n" ); document.write( " \n" ); document.write( ". \n" ); document.write( "Do the algebra on the right side to get: \n" ); document.write( ". \n" ); document.write( " \n" ); document.write( ". \n" ); document.write( "That's the solution you need. Notice that if the \"<\" sign were replaced by an equal sign \n" ); document.write( "you would have an equation in the slope-intercept form. The slope would be \n" ); document.write( "and the y-intercept would be -2. \n" ); document.write( ". \n" ); document.write( "If you graphed this equation \n" ); document.write( ". \n" ); document.write( " \n" ); document.write( ". \n" ); document.write( "The graph would look like: \n" ); document.write( ". \n" ); document.write( " \n" ); document.write( ". \n" ); document.write( "How do we interpret this? We know that the equation for this graph is: \n" ); document.write( ". \n" ); document.write( " \n" ); document.write( ". \n" ); document.write( "but when we add the inequality sign that we got, it tells us that y must be below this \n" ); document.write( "graph (or less than the graphed line, if you prefer). So shade in everything below \n" ); document.write( "this line. That shaded area is the region of all values of y that satisfy the inequality. \n" ); document.write( ". \n" ); document.write( "Note that y cannot be on the line because the inequality sign says \"less than\". If the sign \n" ); document.write( "was \"less than or equal to\" then y could be on the graphed line as well as below it. \n" ); document.write( ". \n" ); document.write( "Hope this helps you to understand a little more about solving inequalities and graphing them \n" ); document.write( "as well. \n" ); document.write( " |