(ax+by)^2+4(mx-ny)(ax+by)+4(mx-ny)^2 = [ (ax + by) + 2(mx - ny) ] ²所以原式=[ (ax + by) + 2(mx - ny) ] ² +2[ (a + 2m)x + (b - 2n)y ] + 1.=[ (a + 2m)x + (b - 2n)y ] ² + 2[ (a + 2m)x + (b...