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Sign convention


A scientist at NASA is closely inspecting the giant concave mirror at the heart of the Hubble telescope. He sees an upright, and magnified, virtual image of himself forming behind the mirror, as shown.
The object is labelled start text, O, end text, and the image is labelled start text, I, end text.
Choose the correct sign for each distance according to the sign conventions for mirrors.
left parenthesis, plus, right parenthesis
left parenthesis, minus, right parenthesis
start text, I, m, a, g, e, space, d, i, s, t, a, n, c, e, end text
start text, F, o, c, a, l, space, l, e, n, g, t, h, end text
start text, O, b, j, e, c, t, space, h, e, i, g, h, t, end text