由一元二次方程根与系数的关系可知x1＋x2=－(-4)/1=4x1x2 = 2k+1/1=2k+1已知x1²+x2²=10∵ (x1＋x2)2= x1²+2 x1x2 +x2²∴(x1＋x2)2= x1² +x2²+2 x1x2即42=10+2（2k+1）解得 k = 1...