Question

What is an equation of the line that passes through the point (-2 0) and is parallel to line x+2y=18?

Answer 1

Method 1

We have ,

x+2y=18

slope of eqn(m1)=-1/2

let m be slope of line

As question both are parallel so,

m1=m

m=-1/2

we have passing point(-2,0)=x1,y1

Now,

y-y1 =m(x-x1)

y-0= -1/2(x-(-2))

2y=-x-2

x+2y+2=0 is the required eqn..

Method 2

Another way of solving:

Given Eqn.

x+2y=18

we know parallel lines only have different Constant term So,

Required eqn is:

x+2y=k

putting value of passing point (-2,0)

we get,

-2 +0 =k

k=-2

putting value if k in above eqn we get,

x+2y=-2

x+2y-2=0 is required eqn.