Write an equation of a circle with the given center and radius center (-7,-6) and radius 2
a)(x+7)^2+(y+6)^2=4
b)(x-7)^2+(y-6)^2=2
c)(x+7)^2+(y+6)^2=2
d)(x-7)^2+(y+6)^2=4

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.