pls help me i will give u a medal the question is in a file

Question

pls help me i will give u a medal  the question is in a file

hari5719 · Answer

pleases help me with this  @MARC_

hari5719 · Answer

@sophiathehuman   and @MARC_  i need help with this one pls

hari5719 · Answer

@butterflydreamer

hari5719 · Answer

@wio ,  @mathslover   @sumanta   @Hero  @ganeshie8   @iambatman   @bibby  @Ashleyisakitty    @TheSmartOne

hari5719 · Answer

@mathslover   @bibby  @MARC_    HELP ME ANYBODY INTRESTED IN HELPING

anonymous · Answer

take a screenshot and paste it here dude, can't process docs here!

hari5719 · Answer

@SandeepReddy  now can u help me plsss

anonymous · Answer

sorry buddy, I don't remember the exact formulae :)

hari5719 · Answer

ok

hari5719 · Answer

attachment

anonymous · Answer

do u think of any theorems of these type?

hari5719 · Answer

no

anonymous · Answer

|dw:1420968586584:dw|
$$BA=BO+OA = -b+a=a-b.$$
use the same methodology in the rest 
I will do just one more:
$$BN=BA-NA= BA-0.5BN$$ 
$$BN=\frac{ 2 }{ 2 }BA$$
 and you got BA.