Calculus| If 𝑢= 𝑥^3+𝑦^3+𝑧^3+3𝑥𝑦𝑧 | show that 𝑥 𝜕𝑢/𝜕𝑥+𝑦 𝜕𝑢/𝜕𝑦+𝑧 𝜕𝑢/𝜕𝑧=3𝑢

In this video I describe about the partial derivative with the help of a question.
That is
If 𝑢= 𝑥^3+𝑦^3+𝑧^3+3𝑥𝑦𝑧
show that 𝑥 𝜕𝑢/𝜕𝑥+𝑦 𝜕𝑢/𝜕𝑦+𝑧 𝜕𝑢/𝜕𝑧=3𝑢