[tex]x = -2 \Rightarrow f(-2) = -14-9=-23\Rightarrow A(-2, -23)\\x = 5\Rightarrow f(5) = 35-9=26\Rightarrow B(5, 26)\\AB = \sqrt{(x_B - x_A)^2 + (y_B - y_A)^2} = \sqrt{(5+2)^2 + (26 + 23)^2} = \sqrt{7^2+49^2} = \sqrt{7^2 + 7^4} = \sqrt{7^2(1 + 7^2)} = 7\sqrt{50} = 7\sqrt{2\cdot5^2} = 35\sqrt2[/tex]
