Find (analytically) the fixed po∫(s) for each of the following systems. (a) x=g_(1)(x,y)=x-y² y=g_(2)(x,y)=-x+6y (b) x=g_(1)(x,y)=(x²-y²-x-3)/(3) y=g_(2)(x,y)=(-x+y-1)/(3) (c) x=g_(1)(x,y)=