Final answer:
C. -1/2
The slope of a line parallel to the line with equation 2x+y=-7 is option C, which is -1/2.
Step-by-step explanation:
The correct answer is option C. To find the slope of a line parallel to the given line, we first need to put the given equation of the line, 2x + y = -7, into slope-intercept form (y = mx + b), where m represents the slope.
By rearranging the equation, we subtract 2x from both sides to get y = -2x - 7. Thus, the slope of the given line is -2. Since parallel lines have the same slope, the slope of a line parallel to the one given would also be -2.