(2k-1)x^2+2(k+1)x+4＝〔√(2k-1)x〕^2+2(k+1)x+2^2上式是完全平方式时,只能写成如下形式〔√(2k-1)x±2〕^2＝〔√(2k-1)x〕^2±4√(2k-1)x+2^2由等式〔√(2k-1)x〕^2+2(k+1)x+2^2和〔√(2k-1)x〕^2±4√(2k-1)x+2^2...