What is the product? (negative 3 s + 2 t)(4 s minus t) negative 12 s squared minus 2 t squared negative 12 s squared + 2 t squared negative 12 s squared + 8 s t minus 2 t squared negative 12 s squared + 11 s t minus 2 t squared

Consider hydrogen in an excited state n = 5n=5 that emits photons to reach the ground state. there are various possible transitions other than straight to the ground state that can occur; for example, it can drop to the n = 3n=3 state followed by the n = 3n=3 to the ground state transition. which of the possible transitions will result in the emission of a photon in the visible region?