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Grade 11Algebra

A,B,C are real numbers ,a not equal 0 and the quadratic equation ax^2+BC+C=0 has no real roots,then. (A) a+b+C>0. B. a(a+b+C)>0. C b(a+b+C)>0. D C(a+b+C)>0. (Chose the two correct alternative {two answer are there})

Profile image of Yuvraj singh
8 Years agoGrade 11
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1 Answer

Profile image of Arun
8 Years ago

Let me give you a shorter proof.

As there is no real zeroes, f(x) is either greater than zero or less than zero, for all x. As f(x) is continuous, it cannot change sign because it would imply a zero.

Consider x=1, f(1)=a+b+c

So f(0)

f(0) = c

So, c

This argument will enable you to prove more statements like this

a(a+c)^2+b(a+c)+c