Answer:
(x^2 + 2x - 21) sq units
Step-by-step explanation:
Area of the shaded region = Area of the larger rectangle - Area of smaller rectangle
Area of the larger region = x(x+2)
Area of the larger region =x^2 + 2x
Area of the smaller rectangle = 3 * 7
Area of the smaller rectangle = 21 sq. units
Area of the shaded region = x^2 + 2x - 21
Hence the required expression is (x^2 + 2x - 21) sq units
Step-by-step explanation:

If you're trying to find the missing side of the "triangle" (the distance from the house to where the ladder touches the ground), you would use the pythagorean theorem, a²+b²=c². (c is always hypotenuse)
a²+b²=c²
12²+b²=15²
144+b²=225
b²=81
√b²=√81
b=9
Y=6X+9 the A is #1
all you need to do is simp the equation