Question

hmm....

Answer 1

\[\LARGE \frac{x_2-x_1}{y_2-y_1}=slope\]

Answer 2

\[\huge~\rm~\frac{ x_2+x_1 }{ 2},\frac{ y_2+y_1 }{ 2 } \]

Answer 3

\[\huge~\rm~x=\frac{ -b \pm \sqrt{b^2-4ac} }{ 2a }\]

Answer 4

\[\huge d=\sqrt{(x_2-x_1)^2+(y_2-y_1)^2}\]