Resposta :
[tex]A=(1,5)\ B=(4,14)\\a)\\\\d(A,B)=\sqrt{(x_B-x_A)^2+(y_B-y_A)^2}\\d(A,B)=\sqrt{(3)^2+(9)^2}=\sqrt{90}=3\sqrt{10}\\\\b)\\\\m=\frac{y_B-y_A}{x_B-x_A}=\frac{9}{3}=3\\\\y=m(x-x_A)+y_A=3x-3+5\Rightarrow t:y=3x+2:A,B\in t\\\\c)\\y=3x+2\\d)\\m=3,\ n=2\Rightarrow m+n=3+2=5[/tex]