domain is ur x values
y = 2x...when x = -1
y = 2(-1)
y = -2.....(-1,2) satisfies this equation
y = 2x....when x = 0
y = 2(0)
y = 0....(0,0) satisfies it
y = 2x....when x = 1
y = 2(1)
y = 2....so (1,2) satisfies it
y = 2x....when x = 2
y = 2(2)
y = 4....(2,4) satisfies it
y = 2x...when x = 3
y = 2(3)
y = 6.....(3,6) satisfies it
y = 2x...when x = 4
y = 2(4)
y = 8.....(4,8) satisfies it