distribute the parentheses.
so..
x2 + x - 4x - 4
x2 -3x - 4
solve for x.
then the number will be greater than or less than.
2007-04-18 19:47:05
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answer #1
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answered by Anonymous
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(x-4)(x+1) <= 28
x^2 - 4x + x - 4 <= 28
x^2 - 3x - 32 <= 0
With some help from the quadratic equation, this factors out to
(x - [3+√137]/2) (x - [3-√137]/2) <=0
The values that make this equal to zero are [3+√137]/2 and [3-√137]/2. If the product is less than zero, this means they have to have opposite signs. So either
(x - [3+√137]/2) > 0 and (x - [3-√137]/2) < 0
or
(x - [3+√137]/2) < 0 and (x - [3-√137]/2) > 0
In the first case we have x >[3+√137]/2 and x < [3-√137]/2. This is impossible though, because [3-√137]/2 is smaller than [3+√137]/2. But in the second case we have
x < [3+√137]/2 and x > [3-√137]/2.
So the total solution set is
[3-√137]/2 <= x <= [3+√137]/2
2007-04-18 19:55:20
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answer #2
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answered by Anonymous
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First get everything on one side:
(x - 4)(x + 1) <= 28
x^2 - 3x - 4 <= 28
x^2 - 3x - 32 <= 0
Cannot factor. Use quadratic formula:
(3 +/- √(9 - (4)(1)(-32))) /2
3+/- √137 / 2
Roots: (3+ √137)/2, (3 - √137)/2
(x - (3 + √137)/2)(x - (3 - √137)/2) <= 0
Want product less than zero, so one factor has to be positive and one negative. This happens just in between the two roots.
Solution: [(3 - √137)/2, (3 + √137)/2].
2007-04-18 19:48:32
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answer #3
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answered by Anonymous
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a million. 5 2.40 8 3. 947>5x-2 4. 904 5. a million-2/4 6.7x(fifty seven*2)/4 7. eighty 5 8. comparable as #2 9. y=4n basically Kidding, Iv'e been out of faculty for 21 years, i did not like homework and exams then and that i actual do not wanna do them now. lol super attempt nevertheless! sturdy success
2016-10-12 22:08:55
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answer #4
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answered by quellette 4
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(x - 4)(x + 1) ≤ 28
x^2 - 3x - 4 ≤ 28
x^2 - 3x ≤ 32
x^2 - 3x + 9/4 ≤ 32 + 9/4
(x - 3/2)^2 ≤ 137/4
x - 3/2 ≤ ± (1/2)√137
3/2 - (1/2)√137 ≤ x ≤ 3/2 + (1/2)√137
2007-04-18 20:06:28
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answer #5
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answered by Helmut 7
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(x-4)(x+1) =< 28
x^2-3x -4 =< 28
x^2-3x -32 =<0
x+4.35)(x-7.35) =< 0
So -4.35<= x <= 7.35
2007-04-18 20:06:36
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answer #6
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answered by ironduke8159 7
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