Answer:
9x+36
Explanation:
With the given equation Area=1/2(Base*Height), all you need to do here is plug in base and height. The height here can be either side, since you're finding the area of a right triangle, but let's use 18 as the height. If 18 is the height, then x+4 is the length.
Plugging these into the equation gives us:
Area=1/2(18(x+4)
Area=9(x+4)
Area=9x+36