Question

draw the line of reflection that reflects quadrilateral abcd onto quadrilateral abcd.

Explanation:

Step1: Identify corresponding points

Take point $A(-1,1)$ and its image $A'(6,1)$; point $B(-1,6)$ and $B'(6,6)$.

Step2: Calculate midpoint x-coordinate

For points $(x_1,y)$ and $(x_2,y)$, midpoint x is $\frac{x_1+x_2}{2}$.
For $A$ and $A'$: $\frac{-1+6}{2}=\frac{5}{2}=2.5$

Step3: Define reflection line

Since y-coordinates are equal, the line is vertical: $x=2.5$ or $x=\frac{5}{2}$

Answer:

The line of reflection is $\boldsymbol{x=\frac{5}{2}}$ (or $x=2.5$), a vertical line passing through $x=2.5$ on the coordinate plane.