IG2年级 过关卷

Given point A(a, 2) and point B(3, b) are symmetric about the x-axis, then a + 2b = (　　)

• -4

• -1

• -2

• 4

Which of the following calculations is correct? (　　)

• a4•a4 = a16

• (a3)4 = a7

• 12a6b4 + 3a2b - 2 = 4a4b2

• (-a3b)2 = a6b2

Which of the following statements is true? (　　)

• The points equidistant from the ends of a segment lie on the perpendicular bisector of the segment

• Two triangles with three corresponding equal angles are congruent

• The intersection of the three angle bisectors of a triangle is called the centroid of the triangle

• An isosceles triangle is a symmetric figure, and its axis of symmetry is the angle bisector

Given m and n are positive integers, and 2m + 3n = 5, then 4m•8n = (　　)

• 16

• 25

• 32

• 64

If (x - 2)(x + 3) = x2 + ax - b, then the value of a + b is (　　)

• -7

• -5

• 5

• 7

In the figure, AD is the angle bisector of ∠CAF, BD = CD, and DE ⊥ AC at E, DF ⊥ AB intersects the extension of BA at F. The correct conclusions are: ① △CDE ≌ △BDF; ② CE = AB + AE; ③ ∠BDC = ∠BAC; ④ ∠DAF = ∠CBD. The sequence numbers of the correct conclusions are (　　)

• ①②③④

• ②③④

• ①②③

• ①②④

In the figure, point P is a moving point on ray ON, ∠AON = 50°, if △AOP is an isosceles triangle, then ∠A = ______.

In the figure, the traffic prohibition sign is a stop-and-yield sign, which has equal angles in an octagon shape, with the word 'STOP' in the middle, red background, white letters, and white border. This sign indicates that vehicles must stop outside the stop line and look around to confirm safety before proceeding. One interior angle of the octagon is ______.

In triangle ABC, ∠B = 60°, AB = 8, point D is on side BC, and AD = AC. If BD = ______, then the length of CD is ______.

If x2 - (k - 2)x + 9 is a perfect square, then k = ______.