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# The equation whose roots A.M=9 and G.M=4 is

$\begin{array}{1 1}(A)\;x^2+18x+16=0&(B)\;x^2+18x-16=0\\(C)\;x^2-18x+16=0&(D)\;x^2-18x-16=0\end{array}$

Let the roots be $\alpha,\beta$
$\large\frac{\alpha+\beta}{2}$=A.M=$9\Rightarrow \alpha+\beta=18$
G.M=$\sqrt{\alpha\beta}=4\Rightarrow \alpha\beta=16$
$\Rightarrow$ Equation :$x^2-18x+16=0$
Hence (C) is the correct answer.