Answer:
slope = - 1
Step-by-step explanation:
the equation of a line in slope- intercept form is
y = mx + c ( m is the slope and c the y- intercept )
given
x + y = - 7 ( subtract x from both sides )
y = - x - 7 ← in slope- intercept form
with slope m = - 1
Parallel lines have equal slopes
then the slope of a line parallel to it is - 1
