Question

Đã trả lời bởi chuyên gia

Answer 1

HD:

$a, P (x) = x^{7} - 80 x^{6} + 80 x^{5} - 80 x^{4} + . . . + 80 x + 15 P (x) = x^{7} - 80 (x^{6} - x^{5} + x^{4} - . . . - x + 1) + 95 = x^{7} - 80 (\frac{x^{7} + 1}{x + 1}) + 95 v ớ i x = 79 t a c ó P (x) = 79^{7} - 80 . \frac{79^{7} + 1}{79 + 1} + 95 = 79^{7} - 79^{7} - 1 + 95 = 94 b, Q (x) = x^{14} - 10 x^{13} + 10 x^{12} - 10 x^{11} + . . + 10 x^{2} - 10 x + 10 = x^{14} - 10 x (x^{12} - x^{11} + x^{10} . . . - x + 1) + 10 = x^{14} - 10 x . \frac{x^{13} + 1}{x + 1} + 10 v ớ i x = 9, t a c ó Q (x) = 9^{14} - 10.9 . \frac{9^{13} + 1}{9 + 1} + 10 = 9^{14} - 9 (9^{13} + 1) + 10 = 9^{14} - 9^{14} - 9 + 10 = 1 c, R (x) = x^{4} - 17 x^{3} + 17 x^{2} - 17 x + 20 = 17 (x^{4} - x^{3} + x^{2} - x + 1) - 16 x^{4} + 3 = 17 . \frac{x^{5} + 1}{x + 1} - 16 x^{4} + 3 v ớ i x = 16, t a c ó R (x) = 17 . \frac{16^{5} + 1}{16 + 1} - 16 . 16^{4} + 3 = 16^{5} + 1 - 16^{5} + 3 = 4 d, S (x) = x^{10} - 13 x^{9} + 13 x^{8} - 13 x^{7} + . . . + 13 x^{2} - 13 x + 10 = 13 (x^{10} - x^{9} + x^{8} - x^{7} + . . . + x^{2} - x + 1) - 12 x^{10} - 3 = 13 . \frac{x^{11} + 1}{x + 1} - 12 . x^{10} - 3 v ớ i x = 12 t a c ó S (x) = 13 . \frac{12^{11} + 1}{12 + 1} - 12 . 12^{10} - 3 = 12^{11} + 1 - 12^{11} - 3 = - 2$

...Xem thêm

Answer 2

HD:

$a, P (x) = x^{7} - 80 x^{6} + 80 x^{5} - 80 x^{4} + . . . + 80 x + 15 P (x) = x^{7} - 80 (x^{6} - x^{5} + x^{4} - . . . - x + 1) + 95 = x^{7} - 80 (\frac{x^{7} + 1}{x + 1}) + 95 v ớ i x = 79 t a c ó P (x) = 79^{7} - 80 . \frac{79^{7} + 1}{79 + 1} + 95 = 79^{7} - 79^{7} - 1 + 95 = 94 b, Q (x) = x^{14} - 10 x^{13} + 10 x^{12} - 10 x^{11} + . . + 10 x^{2} - 10 x + 10 = x^{14} - 10 x (x^{12} - x^{11} + x^{10} . . . - x + 1) + 10 = x^{14} - 10 x . \frac{x^{13} + 1}{x + 1} + 10 v ớ i x = 9, t a c ó Q (x) = 9^{14} - 10.9 . \frac{9^{13} + 1}{9 + 1} + 10 = 9^{14} - 9 (9^{13} + 1) + 10 = 9^{14} - 9^{14} - 9 + 10 = 1 c, R (x) = x^{4} - 17 x^{3} + 17 x^{2} - 17 x + 20 = 17 (x^{4} - x^{3} + x^{2} - x + 1) - 16 x^{4} + 3 = 17 . \frac{x^{5} + 1}{x + 1} - 16 x^{4} + 3 v ớ i x = 16, t a c ó R (x) = 17 . \frac{16^{5} + 1}{16 + 1} - 16 . 16^{4} + 3 = 16^{5} + 1 - 16^{5} + 3 = 4 d, S (x) = x^{10} - 13 x^{9} + 13 x^{8} - 13 x^{7} + . . . + 13 x^{2} - 13 x + 10 = 13 (x^{10} - x^{9} + x^{8} - x^{7} + . . . + x^{2} - x + 1) - 12 x^{10} - 3 = 13 . \frac{x^{11} + 1}{x + 1} - 12 . x^{10} - 3 v ớ i x = 12 t a c ó S (x) = 13 . \frac{12^{11} + 1}{12 + 1} - 12 . 12^{10} - 3 = 12^{11} + 1 - 12^{11} - 3 = - 2$

2 câu trả lời 3346

Câu hỏi hot cùng chủ đề

Bài viết mới nhất Lớp 8