Question 623042
Formula? No, I don't think so!
Here's one way to get the answer.
Start with:
y = mx+b Find the slope, m:
{{{m = (y[2]-y[1])/(x[2]-x[1])}}} The x's and y's are the coordinates of the two given points, so we substitute:
{{{m = (-1-7)/(5-(-3))}}} Evaluate.
{{{m = (-8)/8}}}
{{{m = -1}}} so now you have:
y = -x+b To find b, substitute the x- and y-coordinates of either of the two given points.  Let's choose (-3, 7) and substitute:
7 = -1(-3)+b Solve for b.
7 = 3+b Subtract 3 from both sides.
b = 4
The final equation is:
y = -x+4
Your answer is almost correct but you'll find that the slope, m, is negative!