Answer:
The answer is [tex](2x+3)^2[/tex].
Step-by-step explanation:
Multiply the coefficient of the squared term and the constant. Then, find the factors that add up to 12:
[tex]4*9=36\\36:\{1*36,2*18,3*12,4*9,6*6\}\\6+6=12[/tex]
Split the middle term:
[tex]4x^2+6x+6x+9[/tex]
Factor by grouping:
[tex][4x^2+6x]+[6x+9]\\2x(2x+3)+3(2x+3)\\(2x+3)(2x+3)\\(2x+3)^2[/tex]