Dose anybody know the answer?

they want a fomula that is in respect to 'b"  sooo..

Step-by-step explanation:

just do the algebra like so..

a/b=c

move 'b" across = sign by multiplying by 1/b  like soo.

(1/b)*(a/b)=  (1/b)*c

a=c/b

then move the 'c' to the other side of the = sign  by multiplying by 1/c

(1/c)*a = (1/c)*(c/b)

a/c = b    

makes sense  , also.. as a way to speed that up.. just remember you can just swap the  'b'  and 'c'  in that first equation  

b = a/c

reduce the friction between its moving parts

step-by-step explanation:

in fact, by reducing the friction between the moving parts of the machine, it is possible to reduce the energy wasted due to this friction; therefore, more input energy is converted into useful work, and this will improve the efficiency of the machine.

step-by-step explanation: