Question

(x+\(\dfrac{1}{6}\)y+3)²

Answer 1

Đề ?

Answer 2

\(\left(x+\dfrac{1}{6}y+3\right)^2=x^2+\dfrac{1}{36}y^2+9+\dfrac{1}{3}xy+6x+y\)

Áp dụng HĐT: (a+b+c)^2 = a^2 + b^2 + c^2 + 2ab + 2bc + 2ac nhé