Question

heeeeeelp

Answer 1

\[\left[ (a+b)+3 \right]^{2}\]

Answer 2

The problem follows the multiplication pattern of (x+y)^2 = x^2 + 2xy + y^2, a perfect square trinomial.

In your problem, the role of x is being played by (a + b).
The role of y is being played by 3.

The expansion is:

(a + b) ^2 + 2*3*((a + b) + b^2

Continue to multiply, then collect like terms, and simplify.