Linear Equation System

a) not possible
b)
x=4y+1
y=2x+1
as x=4y+1,so 4y=x-1 or y=(x-1)/4
but y=2x+!, so 2x+1= (x-1)/4
or 8x+4=x-1
or 8x-x= -1-4 = -5
or 7x = -5
or x = -5/7 and y =2x+1 = (2x -5/7) +1 =-10/7+1 =-3/7
so, x = -5/7 and y = -3/7