From the window we can see the blue sky and green trees .and it i_英语解答

From the window we can see the blue sky and green trees .and it is good for our eyes.中文

人气：460 ℃　时间：2020-01-25 23:49:41

解答

从窗户那我们可看到蓝天绿树,而这有助于保眼已知：a=x的平方-2x-1，b=2x的平方-6x+3，求3a-【（2a-b）-2（a-b）】的值，其中x等于-717