The distance between an object and its upright image is 15.5 cm. If the magnification is 0.7, what is the focal length of the lens being used to form the image?(adsbygoogle = window.adsbygoogle || []).push({});

Answer in units of cm.

So I tried combining the equations p+q=15.5 and -q/p=.7 and still was unable to come up with a correct answer.. How exactly do can you find the focal length with only the magnifaction and distance?

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# Homework Help: Finding focal length given magnification and object distance?

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