Carlotta thinks that 3y + 5y3 is the same as 8y4. Which statement shows that it is NOT the same?

3y + 5y ≠ 8y
3y + 5y3 = 8y3
3(4) + 5(4)3 ≠ 8(4)4
3(4) • 5(4)3 ≠ 8(4)4