1、(1)4,2;
(2)9/4,3/2;
(3)9/13,3/4;
(4)6,3
2、B
3、B
4、(1)x₁= 1,x₂= -3;
(2)x₁= 2,x₂= 1;
(3)x₁= x₂= -3;
5、(1)x₁= 1,x₂= -3;
(2)方程无实数根
6、(1)16,4;
(2)1/64,1/8
7、±7
8、D
9、B
10、
11、
(2)方程无实数根;
(4)x₁= -4,x₂= -5;
12、(1)当x ≥ 1时,x² - (x - 1)- 1 = 0,x₁ = 0(舍去),x₂ = 1;
(2)当x < 1时,x² + x - 1 - 1 = 0,x₁ = -2,x₂ = 1(舍去),
∴ 原方程的解是x₁ = -2(舍去),x₂ = 1