一、填空题 (每空 2分 ,共 2 4分 )1 .一个数的相反数是 2 ,这个数的倒数是 .2 .(- 3) 2 的算术平方根是 .3.一种商品每件成本 m元 ,如果按成本的九折出售 ,则每件亏损元 .4.在函数 y=x+2x+a 中 ,自变量 x的取值范围是 x≥ 2 ,则 a的取值范围是 .5.一个多边形的内角和是外角和 First, fill in the blank (2 points for each space, a total of 24 points) 1. The inverse of a number is 2, the reciprocal of this number is .2 . (- 3) The arithmetic square root of 2 is .3. The cost of m yuan, if sold at a discount of 10% of the cost, then each loss element is 4. In the function y=x+2x+a, the independent variable x is in the range of x ≥ 2, then the value of a is in the range of .5. The inside corner and the outside corner of a polygon