Use the formula of length of the segment:
[tex]A(x_A;\ y_A);\ B(x_B;\ y_B)\\\\|AB|=\sqrt{(x_B-x_A)^2+(y_B-y_A)^2}[/tex]
[tex]A(-3;-7);\ B(5;-1)\\\\|AB|=\sqrt{(5-(-3))^2+(-1-(-7))^2}=\sqrt{8^2+6^2}=\sqrt{64+36}=\sqrt{100}=10\\\\A(-3;-7);\ D(-6;-3)\\\\|AD|=\sqrt{(-6-(-3))^2+(-3-(-7))^2}=\sqrt{(-3)^2+4^2}=\sqrt{9+16}=\sqrt{25}=5[/tex]
[tex]A_{\boxed{ . }}=|AB|\cdot|AD|\\\\A_{\boxed{ . }}=10\cdot5=50\ \text{units}^2 [/tex]
