Question

how do i find an equation of the line ? so it needs to be parallel to y=2x+3, through the point 3,1. how do i do this?

Answer 1

Parallel means that the k values are the same.
y=2x+3, here the k value is 2.

We know the or line has to look like this:
y = 2x + c
We also know that it goes through the point 3,1.
We replace the x and the y

1 = 2*3 + c
1 = 6 + c
-5 = c

Now:
y = 2x - 5

http://www.wolframalpha.com/input/?i=y+%3D+2x+-+5+at+3

Answer 2

say that the eqn is
y=mx+c
Since it is // to y=2x+3
m=2
Applying (3,1)
1=2*3+c
c=-5
y=2x-5

Answer 3

so you found c then placed it in the original equation?

Answer 4

Yes exactly

Answer 5

thanks. is that just for when they are parallel that you use the plus c method? what is the equation for this method so i can use it on other problems?

Answer 6

what if it is perpendicular and what is the equation please?

Answer 7

If y=2x+3 is given as perpendicular to the line
then ur m will b
-1/2

Answer 8

If two lines are perpendicular then
m1*m2=-1
If two lines are parallel then
m1=m2

Answer 9

thanks