Answer:
X^2 -5x -36
Step-by-step explanation:
formula of an area of a rectangle: ab
a-length
b-width
(x+4)*(x-9) = x^2 -5x -36
-2 is the negative solution to the problem
You can define each side of a triangle as A B and C, and define the other triangle as triangle DEF. You can then say that A=D, B=E, AND C=F.