Answer:
The expression for the area is;
[tex]21-12x[/tex]Explanation:
Given that the length of the rectangle is 3 and the width is (7-4x);
[tex]\begin{gathered} l=3 \\ w=7-4x \end{gathered}[/tex]Recall that the area of rectangle can be calculated by multiplying its length by the width.
[tex]A=l\times w[/tex]So, the expression for the area of the given rectangle is;
[tex]\begin{gathered} l\times w \\ 3\times(7-4x) \\ 3(7-4x) \\ 21-12x \end{gathered}[/tex]Therefore, the expression for the area is;
[tex]21-12x[/tex]
