已知:x+y=4,x2-y2=20,则x-y的值是______.
∵x2-y2=20,
∴(x+y)(x-y)=20,
又∵x+y=4,
∴x-y=20÷4=5.
阅读理解。
Tom has the most beautiful garden in our town. Many people take part in“The Nicest Garden
Competition”each year, and Tom wins every time. Mike’s garden is larger than Tom’s. Mike works
harder than Tom and grows more flowers and vegetables, but Tom’s garden is more interesting. He
has made clean paths (小径) and built a wooden bridge (桥) over a pool. I like gardens, too, but I
do not like hard work. Every year, I take part in the garden competition, too, and I always win a little
prize (奖励) for the worst garden in our town.
根据短文内容,填写下列表格。
GardenHowWhyTom’sThe 1. _______There are 2. _______ paths and a wooden bridge. Mike’s
3. ______ than Tom’sHe works harder than Tom. There are 4. ________ . The writer’sthe 5. ______
I dislike hard work.
西红柿叶直接进行处理,所得到的叶蛋白浓缩物是没有毒的。