A) 0
B) 1
C) 2
D) 3
Correct Answer: A
Solution :
Let \[f(x)={{x}^{7}}+14{{x}^{5}}+16{{x}^{3}}\,+30x-420\] \[\Rightarrow \,f'(x)\,=(7{{x}^{6}}\,+70{{x}^{4}}\,+48{{x}^{2}}+30)\,>0\forall x\in R\]\[\therefore \,\,f(x)\] is strictly increasing on R. So, the equation f(X) = 0 will have exactly one real root.You need to login to perform this action.
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