How many corners of $SiO_4$ units are shared in the formation of three-dimensional silicates?

Suppose $A$ and $B$ are two points on the line $2x-y+3=0$ and $P(1,2)$ is a point such that $PA=PB$. Then,the mid-point of $AB$ is

If a convex lens of focal length $80 \, cm$ and a concave lens of focal length $50 \, cm$ are combined together, what will be their resulting power?

If the lines $x^2+2xy-35y^2-4x+44y-12=0$ and $5x+\lambda y-8=0$ are concurrent,then the value of $\lambda$ is

$A$ $10 \mu F$ capacitor is charged by a $100 \text{ V}$ battery. It is disconnected from the battery and is connected to another uncharged capacitor of capacitance $30 \mu F$. During this process,the electrostatic energy lost by the first capacitor is

What is the $IUPAC$ name of the following compound?