u have 4 tems multiplied by each other .. the inequlity will be true as long as the number of the negative sign terms is even.
i. for x< -5 all terms are negative .. so their product is ≥0
ii. at x=-5 the LHS=0
iii. for -5
iv. for x=-1 LHS=0
v. for -1
vi. for x=0 LHS=0
vii. for 0
viii. for x=2 LHS=0
ix. for x>2 all terms are positive so the product is positive
i.e. the solutiom is:
x<=-5, -1<=x<=0, x ≥ 2
2007-05-22 21:17:25
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answer #1
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answered by Ceaser 2
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Hi,
While solving such inequalities, you are not expected to solve for exact values of x, instead the answers will be another inequality or bound, such as x ≥ n, etc.
Here the inequality is given as,
x(x-2)(x+1)(x+5) ≥ 0
That means the inequality is either positive or 0.
if we substitute a bound for x, it should satisfy or solve the equation. There are 4 bounds given, we have to examine whether they satisfy the inequality.
x ≥ 0, fails inequality for the non-zero positive values of x ,which are less than 2, as (x -2) becomes negative and thereby the inequality turns negative. Note that x = 0 satisfies the inequality, as x is a factor.
x ≥ 2, satisfy the inequality in its entire range starting from x = 2 or greater than 2,. At x = 2, (x -2) = 0 and the inequality is satisfied. For non-zero positive values of x greater than 2 all the factors are positive and the inequality is positive. Therefore, x ≥ 2 satisfies the inequality.
x ≥ -1. This includes, in itself, the range x ≥ 0. we have already examined x ≥ 0, which fails the inequality. So x ≥ -1 fails the inequality for the same reason. However the negative values of x greater than or equal to -1, satisfy the equation, but not the entire range x ≥ -1.
x ≥ 5. This is included in the range x ≥ 2, which satisfies the inequality. So x ≥ 5, also satisfies the inequality.
However the solution for the values of x that satisfy the values are given by the following.
x ≤ -5
-1 < x < 0 (includes both -1 and 0)
x ≥ 2
Hope this meets your need. Otherwise post the original question verbatim.
Good luck
2007-05-22 22:19:22
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answer #2
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answered by sudhakarbabu 3
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The answer is x < or equal -5
-1 <(or equal) x <(or equal) 0
x > or equal 2
2007-05-22 21:05:04
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answer #3
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answered by jf_fry 2
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