Answer:
Parallel Line: y = 3x - 5
Perpendicular Line: y = -1/3x + 25/3
Explanation:
The equation given is a linear equation in slope-intercept form, y = mx + b, where m = slope and b = y-intercept. With lines that are parallel to each other, they containt the same slope. So, to form an equation of a line that is parallel to the first equation, the slope = 3. Using the given point (4, 7), x = 4 and y = 7, we can use our slope-intercept form to solve for 'b':
7 = (3)(4) + b or 7 = 12 + b or b = -5
So, our equation for a parallel line would be: y = 3x - 5.
For perpendicular lines, the slope must be the opposite reciprocal of the slope from the first equation. So, if m = 3, than the slope of the perpendicular line must be - 1/3. Using the same point (4, 7) we can use our slope-intercept form to solve for 'b':
7 = (-1/3)(4) + b or 7 = -4/3 + b or b = 25/3
So, our equation for a perpendicular line would be: y = -1/3x + 25/3