题目

解方程组． 答案： 解：， ②×2+①得：7x=14， 解得：x=2， 将x=2代入②得：y=﹣1， 则原方程组的解为． 点评： 此题考查了解二元一次方程组，利用了消元的思想，消元的方法有：代入消元法与加减消元法．选词填空。A. How much B. How many C. How old D. How E. How about【1】—________ scarves do you have?—I have four.【2】—________ are these socks?—They're fifteen yuan.【3】—This black dress is too expensive.________ that one?—It's cheap.【4】—________ do you like this skirt?—It's very pretty.【5】—________ is your brother?—He is two years old.