Answer:
length = (4+7y³)
width = 3y²
Step-by-step explanation:
[tex]12y^2=3y^2\cdot4\\\\21y^5=3y^2\cdot7y^3\\\\GCF(12y^2,\ 21y^5)=3y^2\leftarrow width\\\\\text{The formula of an area of a rectangle:}\\\\A=lw\\\\l-length\\w-width\\\\\text{We have the area of the rectangle:}\ A=12y^2+21y^5=3y^2(4+7y^3)\\\\\text{Conclusion:}\\\\length=\\width=3y^2[/tex]
