Eighth grade mathematics

Friendly reminder: please write down the school, name and seat number on the left for binding.

I. Fill in the blanks (3 points for each small question, 36 points for * * *)

1. The degree of the monomial 2πa2 b is.

2. The value range of the independent variable x in the function y=x+√2x+4 is.

3. point P(m, 1) and point Q(2, n) are symmetrical about x, then m2+N2 = _ _ _ _ _ _.

4. Write a linear function parallel to the image: _ _ _ _ _ _ _ _.

5. Decomposition coefficient ax2-ay2 =

6. The coordinates of the intersection of straight lines and lines are _ _ _ _ _ _ _ _ _.

7. If 4x2 -kxy+y2 is a completely flat mode, then k =. b d。

8. If and are similar projects, =.

9.()C (question 1 1) a

10. As shown in the figure, in △ABC, ∠ c = 90, AD bisects ∠BAC, BC= 10cm, BD=7cm, then the distance from point D to AB _ _ _ _ _ _ _ _ _ cm.

1 1. As shown in the right-angle ABC, ∠ ACB = 90 ∠ A = 30, and CD is the height on the side of the hypotenuse AB. If AB = 4°, BD=.

12. Observe the following formula:1× 3+1= 4 = 2; 2×4+ 1=9=3 ; 3×5+ 1= 16=4 ; 4×6+ 1=25=5 ; -According to the above rules, please use the word containing n (n>0) to express the above rules.

Second, multiple-choice questions (4 points for each small question, 20 points for * * *)

13, the following operation is incorrect ()

a、x2 x3=x5 B 、( x2)3=x6 C、x3+x3=2x6 D 、(-2x)3=-8x3

14, the following are factorized, and the correct one is ().

a、x2-3x+2=x(x-3)+2 B、x4- 16=(x2+4)(x2-4)

c 、( a+2b)2=a2+4ab+4b2 D、x2-2x-3=(x-3)(x- 1)

15, one inner angle of an isosceles triangle is 50, so the degrees of the other two angles are () respectively.

A, 65, 65 B, 58, 80 c, 65, 65 or 50, 80 D, 50, 50.

16, the following is the calculation of students in an exam.

③ ④ ⑤ ⑥

The correct numbers are () a, 1 B, 2 C, 3 D and 4.

17. As shown in the figure, square pieces of paper ABCD, M, N M, N are the midpoint of AD and BC respectively, and BC is

Fold up so that point C falls on point P on MN, and BQ is the crease.

so