document.write( "Question 1209292: Solve the inequality
\n" ); document.write( "(3 - z)/(z + 1) \ge 2 + 1/(z - 7).
\n" ); document.write( "Write your answer in interval notation.
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Algebra.Com's Answer #848118 by greenestamps(13203)\"\" \"About 
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\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( "\"%283-z%29%2F%28z%2B1%29-2-1%2F%28z-7%29%3E=0\"

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\n" ); document.write( "\"%283z-21-z%5E2%2B7z-2z%5E2%2B12z%2B14-z-1%29%2F%28%28z%2B1%29%28z-7%29%29%3E=0\"

\n" ); document.write( "\"%28-3z%5E2%2B21z-8%29%2F%28%28z%2B1%29%28z-7%29%29%3E=0\"

\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( "\"A=%2821-sqrt%28345%29%29%2F6\" = approximately 0.4043041
\n" ); document.write( "\"B=%2821%2Bsqrt%28345%29%29%2F6\" = approximately 6.5956959

\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)
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