First, multiple-choice questions (4 points for each small question, 40 points for * * *)

1, if it makes sense, then the range of letters is ()

:D:

2. The number of quadratic roots in the following formula is ()

⑴ ; ⑵ ; ⑶ ; ⑷ ; ⑸ ; ⑹

A: 2 B: 3 C: 4 D: 5.

3, known, then the value of ()

A:-1 b: 1 c: d:

4, the following calculation is correct ()

:D:

5, the following calculation is correct ()

:D:

6, the following quadratic formula, the same as the quadratic formula is ():

:D:

7. Simplify the quadratic root to get ()

A: B: C: D:30

8. If the root number of the simplest quadratic root is the same, the value of a is ().

A: B: C:a= 1 D:a= — 1

9, the value of the radical is equal to ()

A: -2 B: 2 C:2 D:4

10, the following quadratic formula, can be merged is ().

:D:

Fill in the blanks (4 points for each small question, 40 points for * * *)

1 1, calculation: _ _ _ _ _ _ _;

12, when _ _ _ _ _ _ _ _, the quadratic radical is meaningful in the real number range;

13, calculation: _ _ _ _ _ _ _ _ _;

14, calculation: _ _ _ _ _ _ _ _ _;

15, called a.

16. Contrast size: (fill in ">")

17, the quadratic root is meaningful if;

18, if true, then x satisfies _ _ _ _ _ _ _ _ _ _ _ _;

19. Observe and think about the following calculation process: ∫112 =1,∴ =1,∫/kl.

∴ = 1 1 1。 Guess: =;

20. Please note the following: ; ……

Then the fourth formula is in turn: the law you observe expressed by the equation should be