Let denote the "averaged with" operation: a@b=2a+b. Which of the following distributive laws hold for all numbers x,y, and z? I. x @ (y + z) = (x @ y) + (x @ z)II. x + (y @ z) = (x + y) @ (x + z)III. x @ (y @ z) = (x @ y) @ (x @ z)
(A)
I only
(B)
II only
(C)
III only
(D)
I and III only
(E)
II and III only
Solution — click to reveal
Simplify each operation and see which ones hold true. I.x@(y+z)2x+y+z2x+y+z=(x@y)+(x@z)=2x+y+2x+z=22x+y+zII.x+(y@z)x+2y+z22x+y+z=(x+y)@(x+z)=22x+y+z=22x+y+zIII.x@(y@z)x@2y+z42x+y+z=(x@y)@(x@z)=2x+y@2x+z=42x+y+zII and III only