Given:
A line passes through the points (-3,7) and (9,-5).
To find:
The equation of the line in the form of [tex]y=mx+b[/tex].
Solution:
If a line passes through two points, then the equation of the line is:
[tex]y-y_1=\dfrac{y_2-y_1}{x_2-x_1}(x-x_1)[/tex]
A line passes through the points (-3,7) and (9,-5). So, the equation of the given line is:
[tex]y-7=\dfrac{-5-7}{9-(-3)}(x-(-3))[/tex]
[tex]y-7=\dfrac{-5-7}{9+3}(x+3)[/tex]
[tex]y-7=\dfrac{-12}{12}(x+3)[/tex]
[tex]y-7=-1(x+3)[/tex]
On further simplification, we get
[tex]y-7=-x-3[/tex]
[tex]y-7+7=-x-3+7[/tex]
[tex]y=-x+4[/tex]
Therefore, the equation of the required line is [tex]y=-x+4[/tex].
