Đáp án: cho a/b=3/b=b/aChung minh a=b(voi a+b khong= -3) - [(l) (a/b) = (3/b) = (b/a) ( (a, b ≠ 0) ) ⇒ ( (l) ab = 3b (b^2) = 3a ⇔ ( (l) a = (((b^2))/3) (((b^2))/3)b = 3b ⇔ ( (l) a = (((b^2))/3) (b^2) = 9 ⇔ ( (l) a = (((b^2))/3) [ (l) b = 3 b = - 3 ⇔ ( (l) a = (9/3) = 3 [ (l) b = 3 b = - 3 ⇔ b = a = 3 ]

[(l) (a/b) = (3/b) = (b/a) ( (a, b ≠ 0) ) ⇒ ( (l) ab = 3b (b^2) = 3a ⇔ ( (l) a = (((b^2))/3) (((b^2))/3)b = 3b ⇔ ( (l) a = (((b^2))/3) (b^2) = 9 ⇔ ( (l) a = (((b^2))/3) [ (l) b = 3 b = - 3 ⇔ ( (l) a = (9/3) = 3 [ (l) b = 3 b = - 3 ⇔ b = a = 3 ]

Bac Truong Danh

2 năm trước

cho a/b=3/b=b/a.Chung minh :a=b(voi a+b khong= -3)

Xem đáp án

31 lượt xem

1 câu trả lời

thutrangdoan289

2 năm trước

\[\begin{array}{l} \frac{a}{b} = \frac{3}{b} = \frac{b}{a}\,\,\left( {a,\,b \ne 0} \right) \Rightarrow \left\{ \begin{array}{l} ab = 3b\\ {b^2} = 3a \end{array} \right. \Leftrightarrow \left\{ \begin{array}{l} a = \frac{{{b^2}}}{3}\\ \frac{{{b^2}}}{3}.b = 3b \end{array} \right.\\ \Leftrightarrow \left\{ \begin{array}{l} a = \frac{{{b^2}}}{3}\\ {b^2} = 9 \end{array} \right. \Leftrightarrow \left\{ \begin{array}{l} a = \frac{{{b^2}}}{3}\\ \left[ \begin{array}{l} b = 3\\ b = - 3 \end{array} \right. \end{array} \right. \Leftrightarrow \left\{ \begin{array}{l} a = \frac{9}{3} = 3\\ \left[ \begin{array}{l} b = 3\\ b = - 3 \end{array} \right. \end{array} \right. \Leftrightarrow b = a = 3. \end{array}\]