Question

Answer 1

\(B=4x^2+12x+9-\left(4x^2+6x+4x+6\right)+x^2+2x+1\\ =5x^2+14x+10-4x^2-10x-6\\ =x^2+4x+4\)

Answer 2

\(=\left(2x+3-x-1\right)^2=\left(x+2\right)^2=x^2+4x+4\)