Đề kiểm tra môn Đại số Lớp 7 - Trường THCS Thị trấn Đu (Có đáp án)

TRƯỜNG THCS THỊ TRẤN ĐU BÀI KIỂM TRA ĐIỂM Họ và tên: ................................................................ Môn: Đại số 7 Lớp: 7 (Thời gian làm bài: 45 phút) ĐỀ BÀI Câu 1 (3 điểm): Thực hiện phép tính: 2 5 7 5 5 3 10 18 4 8 3 a)   b) 4  c) 4 0,8 3 2 4 3 2 9 5 5 11 11 Câu 2 (2,5 điểm): Tìm x biết: 3 4 17 a)  x - = b) 3x 2 = 4 c) 2x 3 3 5 5 50 2 5 1 5 1 5 6 5 6 15 Câu 3 (1,5 điểm): Tính giá trị của biểu thức: A 6 2 6 4 3 5 3 2 12 6 12 2 25 4 6 4 3 Câu 4 (2 điểm): Hưởng ứng phong trào “Nuôi lợn nhựa tiết kiệm”, cuối học kì I, bốn chi đội 7A, 7B, 7C, 7D thu được tổng số tiền là 780 nghìn đồng. Biết rằng số tiền của bốn chi đội lần lượt tỉ lệ với 8, 6, 7, 5. Hãy tính số tiền mà mỗi chi đội thu được? 200 Câu 5 (1 điểm): So sánh: 3 300 và 5 BÀI LÀM ............................................................................................................................................................................................................................................. ............................................................................................................................................................................................................................................. ............................................................................................................................................................................................................................................. 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Câu Đáp án Điểm 5 7 5 5 5 7 5 5 9 15 1đ a)     3 2 4 3 3 2 4 3 4 4 2 3 10 18 9 10 18 1đ 1 b) 4  4  9 4 13 2 9 5 4 9 5 4 8 3 4 8 4 3 4 8 3 4 c) 4 0,8 4  4 5 4 5 11 11 5 11 5 11 5 11 11 5 1đ 3 4 17 3 57 57 5 19 a)  x - =  x = x =  x = 0,75đ 5 5 50 5 50 50 3 10 2 b) 3x 2 = 4 3x 2 = 4 hoặc 3x 2 = 4 x = 2 hoặc x = 1 đ 3 2 3 c) 2x 3 3 (ĐK: x ) 2 0,75đ 2x 3 9 2x 12 x 6 (thỏa mãn) Vậy x = 6 2 2 2 5 1 5 1 5 1 1 35 51 5 6 5 6 5  6 6  6 2 6 4 15 6 2 4 3 6 4 3 A M M 3 5 3 2 25 13 5 2 5 51 25 5 3 12 6 12 2 2 6 2  1,5đ 4 6 4 3 6 6 3 4 6 2 2 2 35 6 3 7 3 4 16 M . M 6 25 5 5 5 5 25 Gọi số tiền mà các chi đội 7A, 7B, 7C, 7D thu được lần lượt là x, y, z, t (nghìn đồng) (0 < x, y, z, t < 780) Vì bốn chi đội 7A, 7B, 7C, 7D đã thu được tổng cộng 780 nghìn đồng nên ta có: x + y + z + t = 780 (1) Vì số tiền thu được của bốn chi đội lần lượt tỉ lệ với 8, 6, 7, 5 nên ta có: 4 2đ x y z t x y z t x + y + z t x y z t 780 30 (theo (1)) 8 6 7 5 8 6 7 5 8 6 5 5 8 6 7 5 26 Từ đó, ta tính được: x = 240; y = 180; z = 210; t = 150 (thỏa mãn) Vậy lớp 7A thu được 240 nghìn đồng, lớp 7B thu được 180 nghìn đồng, lớp 7C thu được 210 nghìn đồng, lớp 7A thu được 150 nghìn đồng. 100 200 100 Ta có: 3 300 3300 33.100 33 27100 ; 5 5200 52.100 52 25100 5 Mà 27 > 25 > 0 nên 27100 25100 1đ Vậy 3 300 5 200