若2x+3y﹣z=0且x﹣2y+z=0,则x:z=( )
A:1:3
B:﹣1:1
C:1:2
D:﹣1:7
如图所示,为小丽在“研究影响压力作用效果的因素”实验中所选用的器材在水平桌面上进行的实验过程图示.
若m+n=3,则2m2+4mn+2n2-6的值为( )
—Yeah, she works hard and practices_________ it both in and out of class.