1, in the following calculation, the correct one is ().
a 、( a+b)2=a2+b 2 B 、( a-b)2=a2-b 2
c 、( a+m)(b+n)=ab+mn D 、( m+n)(-m+n)=-m2+n 2
2. The image of linear function y=ax+b in rectangular coordinate system is shown in figure 1, so the result of simplifying | a+b |-| a-b | is as follows.
a、2a B、-2a C、2b D、-2b
4. In △ABC and △A'B'C, there are 1AB = A 'b and 2BC = B 'c
(3) AC = a' c', (4) ∠ A = ∠ A', (5) ∠ B = ∠ B' and (6) ∠ C = ∠ C', the following conditions cannot be guaranteed.
△ ABC△ a' b' c' is ()
a、①②③ B、①②⑤ C、①③⑤ D、②⑤⑥
5. If x>- 1, the value of the polynomial x3-x2-x+ 1 ().
A, greater than 1 B, less than 0 C, not less than 0 D, not more than 0.
9.⊿ABC's three sides A, B and C satisfy: A2+B2+C2-2A-2B = 2C-3, then ⊿ABC is ().
A, right triangle b, isosceles right triangle c, isosceles triangle d, equilateral triangle
10, the straight line Y = X- 1 intersects with the coordinate axis at points A and B, point C is on the coordinate axis, and △ABC is an isosceles triangle, then the most eligible point C is ().
a、4 B、5 C、7 D、8
Second, try your skills (3 points for each small question, 30 points for * * *).
12, the image passing point of a function (-1 2), and the value of function y decreases with the increase of independent variables. Please write the functional relationship that satisfies the above conditions:
16. Which statistical chart is suitable for the following questions?
(1) In order to reflect the change of water level in the Yangtze River during the flood season, relevant personnel should measure the highest water level in the flood season somewhere in the Yangtze River every day.
(2) In order to reflect the monthly average temperature in Nanjing every year1February, the relevant personnel calculated the temperature in Nanjing1February in 2004.
(3) In order to understand the attitude of Nanjing citizens to "spitting will be severely punished" (yes, basically, it doesn't matter, no), a news organization conducted a survey of 1000 citizens.
Answer: (1) (2) (3)
17. If the area and y axis of the triangle surrounded by images with linear functions y = KX-3 and y=x+ 1 are 8, then k =.
18, there is a ship sailing from east to west. Is it 15 in A? There is a lighthouse P, continue sailing 10 nautical mile and arrive at B. It is measured that the lighthouse P is 30 north by west. If the course of the ship remains the same, the nearest distance between the lighthouse and the ship is.
I can't go down without an answer.