Explanation:
1) if the point A(7;2) and the given line is in slope-interception form, then the required parallel line has the same slope, its equation can be written as: y=-9x+C, where C - unknown number;
2) to calculate the C it is needed to substitute the A(7;2) into the required equation of the parallel line:
2=-9*7+C; ⇒ C=65.
3) the parallel line is: y=-9x+65.
4) if the point A(7;2) and the given line is in slope-interception form, then the slope of the perpendicular line is: (-1)/(-9)=1/9, and the required equation of the perpendicular line can be written as:
y=1/9 *x+C, where C - unknown number;
5) to calculate the C it is enough to substitute the A(7;2) into the required equation of the parallel line:
2=1/9 *7+C; ⇒ C=11/9;
6) the perpendicular line is:
