(1296-18)÷36的值是( )
A．20
B．35.5
C．19
D．36
参考答案：B
Which symbol means "and"? [ ]
A. ﹩
B. ＠
C.＆
D. ﹪
差分方程yx=1-3yx=2·3x的通解为______．
