Answer:
10 square units
Explanation:
The first two vertices are on the line x=3, separated by 3-(-1) = 4 units in the y-direction.
The third vertex has an x-value that is 3-(-2) = 5 units away from the "base" on the line x=3. So, the "height" of the triangle is 5, and its base length is 4.
The area is ...
A = (1/2)bh = (1/2)(4)(5) = 10 . . . . square units