Question

Đã trả lời bởi chuyên gia

Answer 1

$a, {(x - 1)}^{2} - 1 = 0 \Leftrightarrow {(x - 1)}^{2} = 1 \Leftrightarrow x - 1 = 1 h o ặ c x - 1 = - 1 \Leftrightarrow x = 2 h o ặ c x = 0 V ậ y x = \{2; 0\} b, x^{3} - 3 x^{2} + 3 x - 1 = 0 \Leftrightarrow {(x - 1)}^{3} = 0 \Leftrightarrow x - 1 = 0 \Leftrightarrow x = 1 V ậ y x = 1 c, x^{2} + 4 x = 21 \Leftrightarrow x^{2} + 4 x - 21 = 0 \Leftrightarrow (x^{2} + 4 x + 4) - 25 = 0 \Leftrightarrow {(x + 2)}^{2} = 25 \Leftrightarrow x + 2 = 5 h o ặ c x + 2 = - 5 \Leftrightarrow x = 3 h o ặ c x = - 7 V ậ y x = \{- 7; 3\}$

$d, {(2 x - 1)}^{2} + {(x + 3)}^{2} - 5 . (x + 7) (x - 7) = 0 \Leftrightarrow 4 x^{2} - 4 x + 1 + x^{2} + 6 x + 9 - 5 x^{2} + 245 = 0 \Leftrightarrow 2 x + 255 = 0 \Leftrightarrow 2 x = - 255 \Leftrightarrow x = \frac{- 255}{2} V ậ y x = - 255 / 2$

$3, x^{3} + x^{2} + \frac{1}{3} x + \frac{1}{27} = 0 \Leftrightarrow x^{3} + 3 x^{2} . \frac{1}{3} + 3 x . \frac{1}{9} + \frac{1}{27} = 0 \Leftrightarrow {(x + \frac{1}{3})}^{3} = 0 \Leftrightarrow x + \frac{1}{3} = 0 \Leftrightarrow x = \frac{- 1}{3} V ậ y x = - 1 / 3$ .

...Xem thêm

Answer 2

$a, {(x - 1)}^{2} - 1 = 0 \Leftrightarrow {(x - 1)}^{2} = 1 \Leftrightarrow x - 1 = 1 h o ặ c x - 1 = - 1 \Leftrightarrow x = 2 h o ặ c x = 0 V ậ y x = \{2; 0\} b, x^{3} - 3 x^{2} + 3 x - 1 = 0 \Leftrightarrow {(x - 1)}^{3} = 0 \Leftrightarrow x - 1 = 0 \Leftrightarrow x = 1 V ậ y x = 1 c, x^{2} + 4 x = 21 \Leftrightarrow x^{2} + 4 x - 21 = 0 \Leftrightarrow (x^{2} + 4 x + 4) - 25 = 0 \Leftrightarrow {(x + 2)}^{2} = 25 \Leftrightarrow x + 2 = 5 h o ặ c x + 2 = - 5 \Leftrightarrow x = 3 h o ặ c x = - 7 V ậ y x = \{- 7; 3\}$

$d, {(2 x - 1)}^{2} + {(x + 3)}^{2} - 5 . (x + 7) (x - 7) = 0 \Leftrightarrow 4 x^{2} - 4 x + 1 + x^{2} + 6 x + 9 - 5 x^{2} + 245 = 0 \Leftrightarrow 2 x + 255 = 0 \Leftrightarrow 2 x = - 255 \Leftrightarrow x = \frac{- 255}{2} V ậ y x = - 255 / 2$

$3, x^{3} + x^{2} + \frac{1}{3} x + \frac{1}{27} = 0 \Leftrightarrow x^{3} + 3 x^{2} . \frac{1}{3} + 3 x . \frac{1}{9} + \frac{1}{27} = 0 \Leftrightarrow {(x + \frac{1}{3})}^{3} = 0 \Leftrightarrow x + \frac{1}{3} = 0 \Leftrightarrow x = \frac{- 1}{3} V ậ y x = - 1 / 3$ .

1 câu trả lời 582

Câu hỏi hot cùng chủ đề

Bài viết mới nhất Lớp 8