document.write( "Question 595164: What answer do I leave in absolute value when the equation of the other part does not factor. Here's the problem I'm talking about:
\n" );
document.write( "|12x^2-x-2|=1
\n" );
document.write( "One side already factored is
\n" );
document.write( "X=3/2 x=-1
\n" );
document.write( "The other side canbit be factored. Do I have to put 0 or just give the ones I got? \n" );
document.write( "
Algebra.Com's Answer #377021 by bucky(2189)![]() ![]() ![]() You can put this solution on YOUR website! Let's start from the beginning. \n" ); document.write( ". \n" ); document.write( "I generally work these absolute value problems as two separate problems. I do this in two steps. First, I assign a plus sign to the entire quantity inside the absolute value signs and work that as one problem without using the absolute value signs. Second, I assign a minus sign to the entire quantity inside the absolute value signs and work that as a second problem without the absolute value signs. \n" ); document.write( ". \n" ); document.write( "How does this system work for this problem? Here we go ... \n" ); document.write( ". \n" ); document.write( "The quantity inside the absolute value signs is (12x^2 - x - 2). Put a + sign in front of this quantity and it becomes just 12x^2 - x - 2. Now ignoring the absolute value signs of the original problem, the original problem is reduced to solving: \n" ); document.write( ". \n" ); document.write( "12x^2 - x - 2 = 1 \n" ); document.write( ". \n" ); document.write( "Subtract 1 from both sides to get rid of the 1 on the right side and you get the standard quadratic form: \n" ); document.write( ". \n" ); document.write( "12x^2 - x - 3 = 0 \n" ); document.write( ". \n" ); document.write( "The easiest way to solve for x in this equation is to use the quadratic formula which as you should know by now says that for the standard quadratic form: \n" ); document.write( ". \n" ); document.write( " \n" ); document.write( ". \n" ); document.write( "the answers for x are given by the form: \n" ); document.write( ". \n" ); document.write( " \n" ); document.write( ". \n" ); document.write( "For this problem, a (the multiplier of the x^2 term is +12, b (the multiplier of the x term) is -1, and c (the constant term) is -3. I'll leave you with the job of substituting these three values into the equation for x, but when you do you should get as the answers for x: \n" ); document.write( ". \n" ); document.write( " \n" ); document.write( ". \n" ); document.write( "which if you convert to decimals results in the two values for x being x = 0.543399774116 and x = -0.460066440783. \n" ); document.write( ". \n" ); document.write( "That's half the answer to this problem. We got these two values for x by assigning a plus sign to the quantity inside the absolute value signs of the original problem. \n" ); document.write( ". \n" ); document.write( "Next, let's assign a minus sign to the quantity inside the absolute value signs and go through a similar exercise. Begin with the minus sign assigned as follows: \n" ); document.write( ". \n" ); document.write( "-(12x2 - x - 2) \n" ); document.write( ". \n" ); document.write( "Ignore the absolute value signs and set this quantity equal to 1 as the original problem requires. This second equation becomes: \n" ); document.write( ". \n" ); document.write( "-(12x2 - x - 2) = 1 \n" ); document.write( ". \n" ); document.write( "You can remove the parentheses on the left side by changing the signs of all the terms inside to get: \n" ); document.write( ". \n" ); document.write( "- 12x^2 + x + 2 = 1 \n" ); document.write( ". \n" ); document.write( "Again, get rid of the + 1 on the right side by subtracting 1 from both sides to get the standard quadratic form of: \n" ); document.write( ". \n" ); document.write( "- 12x^2 + x + 1 = 0 \n" ); document.write( ". \n" ); document.write( "Apply the quadratic formula as we did in the first part. This time a (the multiplier of the x-squared) is -12, b (the multiplier of the x) is +1, and c (the constant) is +1. \n" ); document.write( ". \n" ); document.write( "Substituting these values into the form: \n" ); document.write( ". \n" ); document.write( " \n" ); document.write( ". \n" ); document.write( "results in the two values: \n" ); document.write( ". \n" ); document.write( " \n" ); document.write( ". \n" ); document.write( "which, by taking the square root of 49, reduces to: \n" ); document.write( ". \n" ); document.write( " \n" ); document.write( ". \n" ); document.write( "When you work this out, you get the two answers for x as: \n" ); document.write( ". \n" ); document.write( " \n" ); document.write( ". \n" ); document.write( "So, in summary, for this problem we end up with four answers for x as follows: \n" ); document.write( ". \n" ); document.write( "x = 0.543399774116, -0.460066440783, -1/4, and 1/3 \n" ); document.write( ". \n" ); document.write( "I hope this process of working the problem as two different problems, one with a plus sign preceding the entire quantity inside the absolute value signs, and one with a minus sign preceding the entire quantity inside the absolute value signs, is something that you can use to help you get through such problems. I found that it helped me to eliminate some confusion with such problems, and it works because it's just a way of applying the basic definition for absolute value. \n" ); document.write( " \n" ); document.write( " |