Answer: 18.7
Step-by-step explanation:
Find the lengths of AB, BC, and CA
AB =
= 5
≈ 7.1
BC =
= 5
≈ 7.1
CA =
= 2
≈ 4.5
7.1 + 7.1 + 4.5 = 18.7
Answer: (c) y<=-x+4
The area is shaded UNDER the boundary line, hence "<"
The boundary is plotted as solid line, hence "="
The square of a binomial is written like

In your case, you have
, which implies 
So, we want to write

But our left hand side is

If we add 26 to both sides, we have

Answer:
The first set of ordered pairs is a function, because no two ordered pairs have the same first coordinates with different second coordinates. The second example is not a function, because it contains the ordered pairs (1,2) and (1,5). These have the same first coordinate and different second coordinates.