Step 1: We have the following recursive formula:
Un = 0.75Un-1 + 210 where n > 1 and U0 = 450
Step 2: Let's find U1:
U1 = 0.75 * 450 (U0) + 210
U1 = 337.5 + 210
U1 = 547.5
Step 3: Let's find U2:
U2 = 0.75 * 547.5 (U1) + 210
U2 = 410.625 + 210
U2 = 620.625