写一个关于x的一元二次方程,使(1)它的两个根是x1=2,x2=﹣1;(2)该方 发布时间:2017-04-18 21:43 │ 来源:www.tikuol.com 题型:填空题 问题: 写一个关于x的一元二次方程,使(1)它的两个根是x1=2,x2=﹣1;(2)该方程无实根.(1) ;(2) .
题型:填空题 The latch of a safety hook().A.increases the strength of the hookB.prevents the sling ring from coming out of the hook if the strain is abruptly easedC.prevents the sling ring from coming out of the hook if there is a strain on the sling ringD.All of the above 查看答案