Hi there!
[tex]\large\boxed{y = -x + 7}[/tex]
To begin, we must use the slope formula to calculate the slope of the line:
[tex]m = \frac{y_2-y_1}{x_2-x_1}[/tex]
Plug in the coordinates:
[tex]m = \frac{-5-(-2)}{12-9}[/tex]
Simplify:
[tex]m = \frac{-3}{3} =-1[/tex]
Recall that the equation for a line in point-slope form is:
y - y1 = m(x - x1)
Plug in coordinates into the equation along with the slope:
y - (-2) = -1(x - 9)
Simplify:
y + 2 = -x + 9
y = -x + 7