题目

I am Frank Green. I'm now a Grade Seven student in No.10 Middle School. Now let me tell you something about my favorite teacher.My favorite teacher is Mrs. Brown. She is my English teacher. She is my friend Amanda's aunt, too. She has 2 daughters. They are Tina and Tara. And they are twins(双胞胎). They are 13. Mrs Brown is good to every student in my class. Everyone likes her very much. She gives us interesting homework every day. It's relaxing（令人放松的） for me to do homework.Now Mrs. Brown is 40. She has many things to do every day. She has 2 classes in the morning .And she has17．已知两条直线l1：2x+y-2=0与l2：2x-my+4=0．（1）若直线l1⊥l2，求直线l1与l2交点P的坐标；（2）若l1，l2以及x轴围成三角形的面积为1，求实数m的值．