First, solve the equation for slope-intercept form:
y = -1x + b
We can plug either points in for x and y, I chose (-3, -14)
-14 = -1 (-3) + b
-14 = 3 + b
-17 = b
Full Equation:
y = -1x-17
Solve for -17 and we get standard form
y = -x - 17
x + y = -17