x^2-4y^2+x+3y-1=0 (1)2x-y-1=0(2)由(2)得y=2x-1. (3)代入(1)得x^2-4(2x-1)^2+x+3(2x-1)-1=0.即-15x^2+23x-8=0.解得x1=1,x2=8/15.将x1,x2分别代入(3),得原...