Answer :
[tex]m = \frac{y_2 - y_1}{x_2 - x_1} = \frac{5 - 1}{2 - 4} = \frac{4}{-2} = -2 [/tex]
[tex]y - y_1 = m(x - x_1)[/tex]
[tex]y - 1 = -2(x - 4)[/tex]
[tex]y - 1 = -2x + 8[/tex]
[tex]y = -2x + 9[/tex]
[tex]y - y_1 = m(x - x_1)[/tex]
[tex]y - 1 = -2(x - 4)[/tex]
[tex]y - 1 = -2x + 8[/tex]
[tex]y = -2x + 9[/tex]