A:That's the playground. We can play football there.
B:That's the classroom. We can have lessons there.
太阳耀斑活动的周期约是( )
如果一元二次方程x2﹣2x﹣3=0的两根为x1、x2,则x12x2+x1x22的值等于( )
用分数表示下面各式的商.
5÷9= ____
13÷14= ____
x
2.1
2.2
2.3
2.4
2.5
2.6
2.7
2.8
x2﹣2x﹣2
﹣1.79
﹣1.56
﹣1.31
﹣1.04
﹣0.75
﹣0.44
﹣0.11
0.24