How is perpendicular line for 3x-7y=5 be y=(-7/3)X + 8?

Question

3x - 7y = 5
turns into

y = (3/7)x + (-5/7)

slope perpendicular would be (-7/3)X

My teachers answer was "Y= (-7/3)X + 8"

Question is, how do you get "+8"? I understand the slope but not the "8"

question says "Write a line that is perpendicular to 3x-7y=5"

Teacher gave the answer as Y=(-7/3)x + 8

I understand if the question was like.."what is the line perpendicular do 3x-7y=5 when passing though point (X,Y).. that would make things ALOT easier...

Maybe teacher messed up?

Answer 1

No matter what the intercept (b) is, as long as the slope(m) is -7/3 it will intersect the first line at a right angle, therefore being perpendicular.

Answer 2

y=(-7/3)x + 8 is perpendicular with y = (3/7)x + (-5/7)
in a Point n(Xn;Yn)
(there is infinity of perpendicular lines to y = (3/7)x + (-5/7))
to find this point make:
y = (3/7)x + (-5/7)=(-7/3)x + 8 so
(3/7)x + (-5/7)=(-7/3)x + 8.........(1)
(solve this equation to find n where the two line across)

Answer 3

You are right the slope will be -7/3 but we cannot figure out the intercept(i.e. 8) if a point or additional info is not given.

Answer 4

actually to find eq of a line we should know eithe
1)two points on the line
2)one point and slope of the line

according to ur question from the given line we can get the slope of the required line so we should know the point on the line so please read the question once again i think some where u missed to read about the point on the line