The point-slope form of line:
[tex]y-y_1=m(x-x_1)[/tex]
The fomula of a slope:
[tex]m=\dfrac{y_2-y_1}{x_2-x_1}[/tex]
Substitute the coordinates of the points:
[tex]m=\dfrac{7-3}{2-(-2)}=\dfrac{4}{2+2}=\dfrac{4}{4}=1\\\\y-7=1(x-2)[/tex]
[tex]y-7=x-2[/tex] subtract y from both sides
[tex]-7=x-y-2[/tex] add 2 to both sides
[tex]-5=x-y\to\boxed{x-y=-5}[/tex]
