Kiểm tra phần Hằng đẳng thức

BÀI KIỂM TRA SỐ 2
PHẦN: NHỮNG HẰNG ĐẲNG THỨC ĐÁNG NHỚ
Đềbài
Câu 1: Tính: (3đ)
(x2 – x3).(x – 5)
(x + 3).(x2 – 3x + 9)
(2x + y2).(2x – y2)
25x2 – 10x + 1
Câu 2: Rútgọn: (3đ)
(x - 2).(x2 + 2x +4) – 6x2 + 12x
(2x + 5).(5 – 2x) + (x - 5).(5 + 4x)
4x2 + 4x + 1 – ( 2x – 1)2
(x + 5).(x2 + 5x + 25) – 10x.(x + 5) – x3
Câu 3: Chứng minh rằng: (1,5đ)
(a + b).(a2 – ab + b2) + (a – b).(a2 + ab + b2) = 2a3
(a - b)2 + 2ab = a2 + b2
(a2 + b2).(c2 + d2) = (ac + bd)2+ (ad – bc)2
Câu 4: Tínhgiátrịcủacácbiểuthứcsau: (1đ)
x2 – y2tại x = 87 và y = 13
x3 – 3x2 + 3x +1 tại x= 101
Câu 5: Chứng minh rằng: ( 0,5đ)
X2– 6x + 10 > 0 vớimọi x
Câu 6: Tìmgiátrịlớnnhất: (1đ)
x – x2
2x – 2x2 -5

Bàilàm:
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