First find slope (m):
[tex]\sf \bold{slope-formula: {\frac{y2-y1}{x2-x1} }}[/tex]
[tex]\rightarrow \sf \dfrac{9-3}{-14-7}[/tex]
[tex]\rightarrow \sf \dfrac{6}{-21}[/tex]
[tex]\rightarrow \sf -\dfrac{2}{7}[/tex]
equation:
y - y₁ = m ( x - x₁ )
[tex]\rightarrow \sf y - 3 = -\dfrac{2}{7} ( x - 7)[/tex]
[tex]\rightarrow \sf y = -\dfrac{2}{7} x +2 +3[/tex]
[tex]\rightarrow \sf y = -\dfrac{2}{7} x +5[/tex]