AB= 5.65
Explanation
when you have 2 points P1 and P2 , the distance between P1 and P2 is given by:
[tex]\begin{gathered} \text{distance}=\sqrt[]{(x_2-x_1)^2+(y_2-y_1)}^2 \\ where \\ P1(x_1,y_1) \\ P2(x_2,y_2) \end{gathered}[/tex]Step 1
Let
P1=A(-4,2)
P2=B(0,-2)
now, replace
[tex]\begin{gathered} \text{distance}=\sqrt[]{(x_2-x_1)^2+(y_2-y_1)}^2 \\ \text{distance}=\sqrt[]{(0-(-4))^2+(-2-(2)_{})}^2 \\ \text{distance}=\sqrt[]{(4^2)+(-4^2)} \\ \text{distance}=\sqrt[]{16+16} \\ \text{distance}=\sqrt[]{32} \\ \text{distance}=5.65 \end{gathered}[/tex]I hope this helps you