Question

Write an equation of the line perpendicular to the line 8x+15y=12 and containing the point (11,17) write the answer in standard form

Answer 1

The slope of a line perpendicular to another line has a slope which is the negative reciprocal of that line or:

m1 = -1/m2

First, we convert the given equation into slope-intercept form of a line: y = mx + b

8x + 15y = 12

15y = -8x + 12

y = (-8/15) x + 0.8

m1 = -8 / 15

 

Therefore the slope of the perpendicular line is:

m2 = 15 / 8

 

Since the perpendicular line crosses the point (11, 17), therefore using the slope formula:

m = (y2 – y1) / (x2 – x1)

15 / 8 = (y2 – 17) / (x2 – 11)

1.875 (x2 – 11) = y2 – 17

1.875 x2 – 20.625 = y2 – 17

y2 = 1.875 x2 – 3.625

y = (15/8) x – 3.625

multiplying both sides by 8:

8y = 15x – 29

rewriting in standard form:

15x – 8y = 29                (ANSWER)