Preheat your oven to 400°F. Line a large baking sheet with parchment paper for easy cleanup.
In a large bowl, combine the broccoli, cherry tomatoes, and baby carrots. Drizzle with 1 tablespoon of olive oil, and season with salt, pepper, garlic powder, onion powder, and dried oregano. Toss until the vegetables are well coated.
Spread the seasoned vegetables evenly on one side of the prepared baking sheet.
Pat the salmon fillets dry with paper towels and place them on the other side of the baking sheet. Drizzle with the remaining tablespoon of olive oil and season with salt and pepper. Top each fillet with lemon slices.
Bake in the preheated oven for 15-20 minutes, or until the salmon is cooked through and flakes easily with a fork, and the vegetables are tender.
Serve immediately, garnished with additional lemon slices if desired.