Question

What is the solution for the identity used in the diagram?

Answer 1

Area of full rectangle $=$ area of pink square $+$ area of yellow rectangle $+$ area of blue rectangle $+$ area of green rectangle.
i.e., $(3p+1)(3p+3)=(3p{)}^2+3p+9p+3$
$(3p+1)(3p+3)=(3p{)}^2+p(3+9)+3$
So, $(3p+1)(3p+3)=(3p{)}^2+p(3+9)+3$ is solution for the given diagram.