To find the slope of a line given the coordinates of two points, you should use the formula, Slope=y2-y1/x2-x1.
To find the slope of a line which contains the coordinates (8,-3) and (-2,7), you should substitute them into the previous mention formula.
Slope=y2-y1/x2-x1
Slope=(7--3)/(-2-8)
Slope=(10)/(-10)
Slope=-1
The slope of the line which contains the coordinates (8,-3) and (-2,7) is -1 or in other words letter A from the given choices.