Answer:
y = -x + 4
Explanation:
The equation of a line follows the form y=mx+c, where x and y are the coordinates, c is the y-intercept (the value of x where the line crosses the y-axis), and m is the slope.
We are given two points/coordinates - (-3,7) and (1,3) - so we know the following is true for our equation:
7=-3m+c
3=m+c
Rearranging the second equation above, we get c=3-m. Sub this into the first one, and we get
7=-3m+3-m
4=-4m
m=-1
Knowing c=3-m, we can say c=3-(-1)=3+1=4
Having found values for m and c, we can now write our equation:
y = -x + 4
Hope this helps :)