Given :
The area of the rectangle = A
[tex]A=49x^2-16[/tex]The given expression is the difference between two squares
[tex]\begin{gathered} 49x^2=7x\cdot7x \\ 16=4\cdot4 \end{gathered}[/tex]So, factor the expression of the area:
[tex]A=(7x+4)\cdot(7x-4)[/tex]So, the answer will be ;
[tex]\begin{gathered} \text{Length }=7x+4 \\ \text{Width =7x-4 } \end{gathered}[/tex]