document.write( "Question 1209292: Solve the inequality
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document.write( "(3 - z)/(z + 1) \ge 2 + 1/(z - 7).
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document.write( "Write your answer in interval notation. \n" );
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Algebra.Com's Answer #848118 by greenestamps(13203) You can put this solution on YOUR website! \n" ); document.write( "The problem would be far more educational if the answers were not so ugly.... \n" ); document.write( "To solve an inequality like this, get everything on the left with 0 on the right and write the expression on the left as a single rational expression. \n" ); document.write( " \n" ); document.write( " \n" ); document.write( " \n" ); document.write( " \n" ); document.write( "The expression is undefined where the denominator is zero -- at z=-1 and z=7. \n" ); document.write( "The expression value is zero where the numerator is zero. The quadratic in the numerator has irrational roots, which for simplicity I will represent with A and B. The values of those roots are \n" ); document.write( " \n" ); document.write( " \n" ); document.write( "The four zeros of the numerator and denominator break the number line into 5 intervals. Use test points or other methods to determine the intervals on which the expression value is greater than or equal to 0. \n" ); document.write( "(1) (-infinity,-1) negative \n" ); document.write( "(2) (-1,A] positive or zero \n" ); document.write( "(3) (A,B) negative \n" ); document.write( "(4) [B,7) zero or positive \n" ); document.write( "(5) (7,infinity) negative \n" ); document.write( "ANSWER: The inequality is true on the two intervals (-1,A] and [B,7) \r \n" ); document.write( "\n" ); document.write( " \n" ); document.write( " |