A= 1
B= -5
C= 10
In order to figure it out, you can think about it like this..
P(7,6), Q(1,6), R(4,2)
We have PQ parallel to the x axis. We'll call that the base,
b = 7 - 1 = 6
The altitude is then the y difference h = 6 - 2 = 4
The area is 
Answer: 12 square units
In general we can use the shoelace formula for the area of any polygon given coordinates. We write the points like this:
(7,6), (1,6), (4,2)
(1,6), (4,2), (7,6)
The area is then half the absolute value of the sum of the cross products:

Answer:
56 cm squared
Step-by-step explanation:
First things first: Cop one triangle off the rectangle, and attach it to the other one, so the shape looks like a L
Now I can actually solve this:
The left side is 8 cm (because y = 8 cm)
The top is 10 cm
The middle is 6 cm
The inside left is 3 cm
And the very bottom is 2 cm
First, we'll solve for the newly constructed rectangle: 3 x 2. That equals 6.
Next, solve for the longer rectangle: 10 x 5. That's 50.
Now, add the two areas, and we get 56. So the area of the whole thing is 56 cm squared.
(Please keep in mind that I could be wrong, so double check it for me, thanks!)
Answer:
3m-3n
Step-by-step explanation:
We want to simplify the expression;
2m - [n - (m - 2n)].
We expand the parenthesis to obtain;
2m - (n - m + 2n)
2m - ( - m + 3n)
Expand further to get;
2m +m -3n
Combine the first two terms;
3m-3n