Solve for x and y: 7y−5x=31 x=4−2y select one: a. x=8,y=−2 b. x=−2,y=3 c. x=−9,y=−2 d. x=3,y=−2

This is a system of equation:

7y - 5x = 31

x = 4 - 2y

Plug in 4 - 2y for x

7y - 5(4 - 2y) = 31

Distribute -5 to both 4 and -2y

7y - 20 + 10y = 31

Simplify

17y - 20 = 31

Isolate the y. Note the equal sign. What you do to one side you do to the other. Do the opposite of PEMDAS.

Add 20 to both sides

17y - 20 (+20) = 31 (+20)

17y = 51

Divide 17 from both sides to isolate the y

17y/17 = 51/17

y = 51/17 or 3

y = 3

Plug in 3 for y in one of the equations.

x=4−2y

x = 4 - 2(3)

Simplify.

x = 4 - 6

x = -2

x = -2, y = 3 is your answer, or B)

hope this helps

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.