[填空题]
(a) How far from a 5+ kuu:v5eb4mf ed*l* r0.0-mm-focal-length lens must an object be placer+ytba m2 ,zp:d if its image is to be magnatp,b:rzy m+2 ified 2.00× and be real? mm
(b) What if the image is to be virtual and magnified 2.00×? mm (formed by some other piece of optics).]
