Analytic geometry (polygon in the coordinate system).
Mark the point on the coordinate system and draw the polygon (attachment).
This is the trapezoid.
The formula of an area of a trapezoid:
[tex]A=\dfrac{a+b}{2}\cdot h[/tex]
a, b - the lengths of the parallel sides
h - the height
Substitute:
[tex]a=9,\ b=7,\ h=8\\\\A=\dfrac{9+7}{2}\cdot8=\dfrac{16}{2}\cdot8=8\cdot8=64[u^2][/tex]
[tex]\huge\boxed{A=64u^2}[/tex]
