问题
填空题
若两直线5x+4y=2k+1和2x+3y=k的交点在第四象限,则整数k的值为______.
答案
将原式组成方程组得
,5x+4y=2k+1① 2x+3y=k②
解得
,x= 2k+3 7 y= k-2 7
由于交点在第四象限,
所以
,
>0 2k+3 7
<0k-2 7
解得-
<k<2.3 2
∴整数k的值为-1,0,1.
若两直线5x+4y=2k+1和2x+3y=k的交点在第四象限,则整数k的值为______.
将原式组成方程组得
,5x+4y=2k+1① 2x+3y=k②
解得
,x= 2k+3 7 y= k-2 7
由于交点在第四象限,
所以
,
>0 2k+3 7
<0k-2 7
解得-
<k<2.3 2
∴整数k的值为-1,0,1.
从方框中选出正确的词完成下列句子。 | |
2. How do people in your area _______ May Day? 3. We _______ a beautiful Christmas tree with colored lights last night. 4. Lily _______ some cards _______ her friends last week. 5. Look at the light! Miss Gao _______ in her bedroom. 6. I want to buy a _______ for my mother. 7. Lily _______ a happy birthday yesterday. 8. They often _______ their stockings by the fireplace. |