SOLUTION: If F is the focal length of a convex lens and an object is placed at a distance x from the lens then its image will be at a distance y from the lens, where F,x, and y are related b

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Question 122450This question is from textbook College Algebra
: If F is the focal length of a convex lens and an object is placed at a distance x from the lens then its image will be at a distance y from the lens, where F,x, and y are related by the lens equation
1/F = 1/x + 1/y
Suppose that a lens has a focal length of 4.8 cm, and that the image of an object is 4cm closer to the lens than the object itself. How far from the lens is the object?
Thank you for your help!!! This question is from textbook College Algebra

Answer by scott8148(6628) About Me  (Show Source):
You can put this solution on YOUR website!
"the image of an object is 4cm closer to the lens than the object itself"
__ y=x-4

1/4.8=(1/x)+(1/(x-4))

multiplying by 24x(x-4) __ 5x^2-20x=24x-96+24x __ 5x^2-68x+96=0

factoring __ (5x-8)(x-12)=0


the two solutions represent the "real" image and the "virtual" image