Answer with explanation:
→The Polygon MAST has coordinates "M(-3,-1), A(-3,2),S (-1,3) T (1,1)".
Now, the polygon is reflected across , line ,x= -3.
Now, the Meaning of reflection is that ,the Shape and size of Image before and after Reflection does not change.
And when you , reflect the polygon which is a quadrilateral having vertices M, A, S, and T, the perpendicular distance from line , x=-3, from each of the vertices of the Quadrilateral,Called Pre-Image, will be same from each of the Vertices of the polygon after Reflection Called Image.
When , "polygon MAST is reflected across line", x=-3, the vertices of Image M'A'S'T' will be
M(-3,-1)→M'(-3,-1)
A(-3,2)→A'(-3,-2)
S(-1,3)→S'(-5,3)
T(1,1)→T'(-7,1)