第一试一、选择题(每小题5分,共50分)1.a、b 为实数,集合 M={b/a,1},P={a,0},f:x→x表示把集合 M 中的元素 x 映射到集合 P 中仍为 x,则 a+b 的值等于().A.-1 B.0 C.1 D.±12.若函数 f(x)满足 f(2/(x+|x|))=log_2(x|x|)~(1/2),则 f(x)的解析式是().A.log_2x B.-log_x C.2~(-x) D.x~(-2)3.若关于 x 的方程(3/2)x=(2+3a)/(5-a)有负数根,则实数 a 的 First try one, multiple choice questions (5 points for each question, total 50 points) 1.a, b are real numbers, set M={b/a,1}, P={a,0},f:x→x Indicates that the mapping of the element x in the set M to the set P is still x, then the value of a+b is equal to (). A.-1 B.0 C.1 D.±12. If the function f(x) satisfies f (2/(x+|x|))=log_2(x|x|)~(1/2), then the analytical expression of f(x) is ().A.log_2x B.-log_x C.2~(- x) Dx~(-2)3. If the equation (3/2) x = (2+3a)/(5-a) for x has a negative root, then the real number a