[填空题]
A microscope uses an e09nrdb;k tol cn s .bb(ww7f y;;a;(lbyepn. ahbvj42e0nqxi( :n u4zu6 he;5ndqiece with a focal length of 1.40 $cm$. Using a normal eye with a final image at infinity, the tube length is 17.5 $cm$ and the focal length of the objective lens is 0.65 $cm$. What is the magnification of the microscope? = $\times$
