Reference answer

First of all, fill in carefully:

1.-5 ; 2.& lt； 3.； 4.5; 5.；

6. 120; 7.； 8.56; 9., ;

10.； 1 1.7; 12.

Second, choose carefully:

13.B 14。 D 15。 A 16。 A 17。 C 18。 C 19。 ; 20. What happened to the original question? Missing the coordinates of the center of the circle

Third, do it seriously.

2 1, solution: original formula = 1+3- 1 = 3.

22. Solution:

=

=

=

When or, the values of are all 2008.

Xiao Ming copied the numerical value wrong, but the result was correct.

23. (1) As shown:

(2) Proof is enough.

24、( 1) 3÷25=0. 12; 25×0.24=6;

(2) ∫ Seven of the 25 contestants scored above 95 (including 95).

The number of students who won the first prize in this competition is 7 ÷ 25× 100% = 28%.

25. Solution: (1) According to the meaning of the question, the coordinates of point C are (0, 1) and the coordinates of point F are (-4,2).

Let the parabolic analytical formula be,

So,

solve

So parabolic analytical formula.

(2) Because the abscissa of point A is -8,

When,,

So the height of the AD column is 5 meters.

26. Solution: (1) According to the meaning of the question, the shadow area S = 50× 32-20× 5× 4-=1200-25 =1125 (square meter);

(2) set the original plan to lay square meters every day, according to the meaning of the question.

solve

Prove to be the root of the original equation.

A: It was originally planned to lay 75 square meters every day.

27. Solution: (1) 1308,1320;

(2) Assuming that the unit needs to print a copy of data,

At that time, the cost of a printing factory was 600+0.3, and the cost of B printing factory was 600+0.3, which was the same for both factories.

At that time, the cost of a printing factory was 600+0.3× 2000+0.3× 90% = 0.27+660.

The cost of printing factory B is 600+0.3, and the cost of printing factory A is lower.

At that time, the cost of a printing factory was 600+0.3× 2000+0.3× 90% = 0.27+660.

The cost of printing plant B is 600+0.3× 80% = 0.24- 120, and the cost of factory B is lower.

28.( 1) because BE‖AC, AB‖CD,

So the quadrilateral ABEC is a parallelogram,

So CE=AB=4,

Therefore, the area of △AED is × 4× (4× 2) =16;

(2) The area of quadrilateral APCD is equal to the area of square ABCD,

Because BE‖AC, the area of △APC is equal to the area of △ABC.

So △APC area +△ ACD area =△ ABC area +△ ACD area = square ABCD area;