Find the average of 7410, 408, 64, and 28,908

Ineed with number 17 i don’t get it at alll

What expression is equivalent to 42x-56y

The linear combination method is applied to a system of equations as shown. 4(.25x + .5y = 3.75) → x + 2y = 15 (4x – 8y = 12) → x – 2y = 3 2x = 18 what is the solution of the system of equations? (1,2) (3,9) (5,5) (9,3)