Here: (Aₓ, Ay) = (-3,-4), (Bₓ, By) = (-7,0), (Cₓ, Cy) = (-3, 4)
Now, Formula of area of triangle is:
area = [Aₓ(By - Cy) + Bₓ(Cy - Ay) + Cₓ(Ay - By)] / 2
Substitute the values in to the expression,
area = [-3(0-4) - 7(-4-(-4)) - 3(-4-0)] / 2
area = [-3(-4) -7(0) -3(-4)] / 2
area = [12-0+12] / 2
area = 24 / 2
area = 12
Final answer would be 12 units.
Hope this helps!