Tìm x, biết:
a) 5x(x -2000) - x + 2000 = 0;
b) x\(^3\) – 13x = 0
a) 5x( x - 2000) - x + 2000 = 0
\(\Leftrightarrow\) 5x(x - 2000) - (x - 2000) = 0
\(\Leftrightarrow\) (x - 2000)(5x - 1) = 0
\(\Leftrightarrow\) x - 2000 = 0 hoặc 5x -1 = 0
\(\Leftrightarrow\) x = 2000 hoặc x = \(\dfrac{1}{5}\)
b) x\(^3\) – 13x = 0
\(\Leftrightarrow\) x(x\(^2\) - 13) = 0
\(\Leftrightarrow\) x = 0 hoặc x\(^2\) -13 = 0
\(\Leftrightarrow\) x = 0 hoặc x = \(\pm\)\(\sqrt{13}\)
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