Answer:
[tex]EF=3\sqrt{10}\ units[/tex] ------> three square root of 10
Step-by-step explanation:
we know that
the formula to calculate the distance between two points is equal to
[tex]d=\sqrt{(y2-y1)^{2}+(x2-x1)^{2}}[/tex]
In this problem we have
[tex]E(-1,-1)\\F(8,-4)[/tex]
substitute the values
[tex]EF=\sqrt{(-4+1)^{2}+(8+1)^{2}}[/tex]
[tex]EF=\sqrt{(-3)^{2}+(9)^{2}}[/tex]
[tex]EF=\sqrt{90}\ units[/tex]
[tex]EF=3\sqrt{10}\ units[/tex]
