document.write( "Question 1209252: What value of x is in the solution set -2(3x+2) > -8x+6
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document.write( "(a) -5
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document.write( "(b) 6
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document.write( "(c) 5
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document.write( "(d) -6 \n" );
document.write( "
Algebra.Com's Answer #847920 by math_tutor2020(3817)![]() ![]() ![]() You can put this solution on YOUR website! \n" ); document.write( "Answer: 6 (choice B)\r \n" ); document.write( " \n" ); document.write( "\n" ); document.write( "-----------------------------------\r \n" ); document.write( "\n" ); document.write( "Work Shown \n" ); document.write( "-2(3x+2) > -8x+6 \n" ); document.write( "-6x-4 > -8x+6 \n" ); document.write( "-6x+8x > 6+4 \n" ); document.write( "2x > 10 \n" ); document.write( "x > 10/2 \n" ); document.write( "x > 5 \n" ); document.write( "Anything larger than 5 is in the solution set. \n" ); document.write( "Of the choices you listed, only x = 6 works as a solution.\r \n" ); document.write( " \n" ); document.write( "\n" ); document.write( "----------------------------------- \n" ); document.write( "Another approach\r \n" ); document.write( " \n" ); document.write( "\n" ); document.write( "Since we're given a list of choices, we can plug them one at a time into the original inequality. \n" ); document.write( "If we get a true statement at the end, then we have a solution.\r \n" ); document.write( " \n" ); document.write( "\n" ); document.write( "Let's try choice (a) \n" ); document.write( "Plug in x = -5 \n" ); document.write( "-2(3x+2) > -8x+6 \n" ); document.write( "-2(3*(-5)+2) > -8*(-5)+6 \n" ); document.write( "-2(-15+2) > 40+6 \n" ); document.write( "-2(-13) > 46 \n" ); document.write( "26 > 46 \n" ); document.write( "The last inequality at the end is false, so the original inequality is false when x = -5. We can rule out choice (a)\r \n" ); document.write( " \n" ); document.write( "\n" ); document.write( "Now let's try choice (b) \n" ); document.write( "Plug in x = 6 \n" ); document.write( "-2(3x+2) > -8x+6 \n" ); document.write( "-2(3*6+2) > -8*6+6 \n" ); document.write( "-2(18+2) > -48+6 \n" ); document.write( "-2(20) > -42 \n" ); document.write( "-40 > -42 \n" ); document.write( "We arrive at a true claim. \n" ); document.write( "It might help to make a (vertical) number line to see that -40 is larger than -42. \n" ); document.write( "Or you can multiply both sides by -1 to go from -40 > -42 to 40 < 42. \n" ); document.write( "Don't forget to flip the inequality sign when multiplying both sides by a negative number. \n" ); document.write( "The last inequality is true, so the original inequality is true when x = 6 \n" ); document.write( "The answer is choice (b)\r \n" ); document.write( " \n" ); document.write( "\n" ); document.write( "You should find that x = 5 and x = -6 will make the inequality false, so we can rule out choices (c) and (d). \n" ); document.write( "I'll let the student handle the scratch work for these cases. \n" ); document.write( " \n" ); document.write( " |