Given:-
The sides of the rectangle are 5 and 9.
To find the area after each side is increased by x.
So after each side is increased by x. we get the side lengths as,
[tex](2x+5),(2x+9)[/tex]
So now we use the formula,
[tex]\begin{gathered} A=l\times b \\ A=(2x+5)(2x+9) \\ A=4x^2+18x+10x+45 \\ A=4x^2+28x+45 \end{gathered}[/tex]
So our required area is,
[tex]4x^2+28x+45[/tex]
