There is a fraction ((x)/(y)) (x, y are not 0), if x expands to its 2 times, y shrinks to its (1/2), then the value of this fraction is expanded to the original how many times
有一个分数((x)/(y))(x、y均不为0)，如果x扩大到它的2倍，y缩小到它的(1/2)，那么这个分数的值扩大到原来的多少倍
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