12. What is the product of (a-5) and (a+3)?
A. A2-15
B. A2+2a-15
C. A2-2a-15
D. AS-2

C. a²-2a-15

Step-by-step explanation:

(a-5) (a+3)

Expand the bracket

a(a+3)-5(a+3)

a²+3a-5a-15

a²-2a-15

See below

Step-by-step explanation:

Part A:

area of parallelogram = base * height

A = 9 ft * 8/9 ft = 8 ft^2

Part B:

Connect point D to point B with a segment. Now you have 2 triangles.

The area of each triangle is base * height/2

area of triangle = bh/2 = (9 ft)(8/9 ft)/2 = 4 ft^2