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    Find the range of values of k for which x^2 +k(x+2) +3(x+1) >0 for all real values of x.
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    try to solve as you usually do with double brackets!
    >0 take as = 0 but do write >0 when solving
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    try to get it in the form ax^2+bx+c>0 (quadratic equation), determine its discriminant Δ which is a function of k. Then solve Δ<0
    Furthermore, working with double brackets keep in mind that not only the product of two positive numbers is greater than zero, but also the product of two negative ones.
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    (Original post by fatima1998)
    try to solve as you usually do with double brackets!
    >0 take as = 0 but do write >0 when solving
    This can lead to problems with quadratic inequalities.
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    (Original post by B_9710)
    This can lead to problems with quadratic inequalities.
    but isn't this just a simple algebra but they put that sign to make it complicated!
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    (Original post by fatima1998)
    but isn't this just a simple algebra but they put that sign to make it complicated!
    Not at all!
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    (Original post by Zacken)
    Not at all!
    oops!! i misunderstood the question
    i thought the question is to find the value of x but it's values of the k
 
 
 
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