Calculate the range of values of c for which 3x^2-9x+c>2.25 for all values of x.
I'm really confused as this is the first time i encountered a quadratic inequality question that has two unknowns without telling the nature of the roots.
Thanks in advance!
I'm really confused as this is the first time i encountered a quadratic inequality question that has two unknowns without telling the nature of the roots.
Thanks in advance!
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If the D (discriminant) in your quadratic formula is zero, that implies that "c" must be 9.
If c=9 there is only ONE VALUE (in the domain of all real numbers) for x that doesn't
satisfy the inequality (3/2). Making the choice of c >9 (!) means that there will be NO
ZERO (x-intercepts). The parabola will ALL BE ABOVE X-AXIS!
Eureka! The range for c is c>9.
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If c=9 there is only ONE VALUE (in the domain of all real numbers) for x that doesn't
satisfy the inequality (3/2). Making the choice of c >9 (!) means that there will be NO
ZERO (x-intercepts). The parabola will ALL BE ABOVE X-AXIS!
Eureka! The range for c is c>9.
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