What is the formula for a rectangular prism

Lena reflected this figure across the x-axis. she writes the vertices of the image as a'(−2, 8), b'(−5, 6), c'(−8, 8), d'(−4, 2).

Divide. –4.2 ÷ 6 = a –0.7 b 0.7 c –7 d 7 me

Lauren has five shells she found on the beach seashells represent one-third of the shells her whole collection how many shells does lauren have in her whole collection