Explanation
Line passes through the points and , so the slope of line is equal to . Lines and are perpendicular, so the slope of line is equal to the negative reciprocal of the slope of line . Therefore, the slope of line is .
Explanation
Line passes through the points and , so the slope of line is equal to . Lines and are perpendicular, so the slope of line is equal to the negative reciprocal of the slope of line . Therefore, the slope of line is .