document.write( "Question 76316: Help me solve this equation in interval notation -1 < 3x + 5 < 8. \n" ); document.write( "
Algebra.Com's Answer #54810 by bucky(2189) ![]() You can put this solution on YOUR website! Given: \n" ); document.write( ". \n" ); document.write( "-1 < 3x + 5 < 8 \n" ); document.write( ". \n" ); document.write( "You need to determine the limits on just +x. You can do this by following the basic \n" ); document.write( "rules of equations ... whatever you do to one section of the inequality, you must also \n" ); document.write( "do to the other 2 sections of the inequality. There is, however, one exception. That \n" ); document.write( "exception is that if you DIVIDE or MULTIPLY one section of the inequality by a NEGATIVE \n" ); document.write( "quantity, you must do the same to all other sections AND you need to REVERSE the DIRECTION \n" ); document.write( "of the inequality signs. \n" ); document.write( ". \n" ); document.write( "Now to this particular problem. To get closer to having just x in the middle section \n" ); document.write( "of the inequality, we can eliminate the +5 by subtracting 5 from all three sections \n" ); document.write( "of the inequality. When you perform that subtraction you get: \n" ); document.write( ". \n" ); document.write( "-6 < 3x < 3 \n" ); document.write( ". \n" ); document.write( "Now to get just x in the middle, divide all three sections by +3 to get: \n" ); document.write( ". \n" ); document.write( "-2 < x < 1 \n" ); document.write( ". \n" ); document.write( "This means that on the number line the x can be anywhere between -2 and +1. \n" ); document.write( ". \n" ); document.write( "That's the answer you need. Note that we did not have to apply the rule that governs \n" ); document.write( "multiplying or dividing by a negative number. But remember that rule because you may \n" ); document.write( "need it for other problems. \n" ); document.write( ". \n" ); document.write( "Hope this helps you to understand what the problem was asking you to do and how you would go \n" ); document.write( "about doing it. \n" ); document.write( " |