Answer:
The first one is
Step-by-step explanation:
12y
Step-by-step explanation: 3(y4)
3×y×4 = 12y
12 = 4 × 3
20 = 4 × 5
12 + 20 = 4 × 3 + 4 × 5 = 4 × (3 + 5)
900π
surface area of a sphere: 4πr²
=> 4 × π × 15²
=> 900π