The value of ${81^{(1/{\log_5}3)}} + {27^{\log_9 36}} + {3^{4/{\log_7}9}}$ is equal to

If the pair of straight lines given by $A x^2+2 H x y+B y^2=0$,where $(H^2 > A B)$,forms an equilateral triangle with the line $a x+b y+c=0$,then $(A+3 B)(3 A+B)=$ (in $H^2$)

$\cos \alpha \sin (\beta-\gamma)+\cos \beta \sin (\gamma-\alpha)+\cos \gamma \sin (\alpha-\beta)$ is equal to

Which of the following groups of mineral elements is present in higher amounts in living organisms?

Which of the following is a bactericidal antibiotic?

Values of the acceleration $A$ of a particle moving in simple harmonic motion as a function of its displacement $x$ are given in the table below. The period of the motion is

$A \; (mm \; s^{-2})$	$16$	$8$	$0$	$-8$	$-16$
$x \; (mm)$	$-4$	$-2$	$0$	$2$	$4$