the slope of the perpendicular line is -9
Explanation:Given equation: 9y = x + 13
Rewritting in the form of slope-intercept form: y = mx + c
We divide both sides by the coefficient of y:
9y/9 = x/9+ 13/9
y = x/9 + 13/9
where m = 1/9
c = 13/9
For a line to be perpendicular to another line, the slope of one will be the negative reciprocal of the second slope
Since the slope of the first line = 1/9
reciprocal of 1/9 = 9/1 = 9
negative reciprocal = -9
The slope of the second is the negative reciprocal of the 1st line
Hence, the slope of the second (slope of the perpendicular line) is -9
