在做光电效应的实验时，某金属被光照射发生了光电效应，实验测得光电子的最大初动能Ekm与入射光的频率ν的关系如图所示，由实验图象不可求出（ ）
阅读短文，判断正误。
It was Saturday yesterday. It was sunny. Li Lei helped his mother do the housework in the morning. He went to the park with his friends in the afternoon. They played football in the park. His sister Li Mei played computer games at home. Their father, Mr. Li, watched TV at home.
求下列各式中x的值．
（1）9x2﹣4=0
（2）（1﹣2x）3=﹣1．
