2.c analysis even function conforms to f(-x)=f(x).

3. The intersection of a ∩ b = {3,4} represents the same element in two sets.

4、x=2？ =8

5、an=[(- 1)^(n+ 1)](3n-2)a5=[(- 1)^6](3×6-2)= 16 a 100=[(- 1)^ 10 1](3× 100-2)=-298

6. Solution 4x-30≤0 4x≤30 x≤30/4=7.5

Solution 6x+24≥0 6x≥-24 x≥-24/6=-4

Simultaneous results of -4≤ x≤7.5

7、f(x)=ax？ +b f( 1)= a+b =- 1 f(2)= 4a+b = 8 3a =(4a+b)-(a+b)= 8-(- 1)= 9 a = 3

b=- 1-a=-4

f(x)=3x？ -4 f(5)=3×5？ -4=3×25-4=7 1