题目

GOOD ENOUGH TO EAT: A kid's guide to food and nutrition(营养)by Lizzy Rockwell★★★★☆ 43 customer reviewsPrice: $6.55 $6.99Want it two days later? Book it now!More choices: $2.51 new(61 offers)$0.33 used(38 offers)GOOD ENOUGH TO EAT is a guide to kids' nutrition written especially for kids. It's a tool for families who want to eat a healthy meal. This book explains nutrition from carrots to cookies. Top Customer Reviews★★★★★My kids loved this book!By L. MarkovitzThis book is very easy to understand for kids and helpful if you want them to understand why you want them to eat已知方程x2－5x＋2 ＝0的两个解分别为x1、x2，则x1＋x2－x1x2，的值为    A．－7             B．－3            C．7                D．3