Given :
The upper base is, a = x - 1.
The lower base is, b = x + 5.
The height is, h = x + 1.
The expression for finding the area of a trapezoid is given by,
[tex]A=\frac{a+b}{2}h[/tex]Substituting the values, we get,
[tex]\begin{gathered} A=\frac{(x-1+x+5)}{2}\times x+1 \\ \text{ =}\frac{\text{2x+4}}{2}\times x+1 \\ \text{ =(x+2)(x}+1)=x^2+3x+2 \end{gathered}[/tex]