# B I need word problems about a pair of straight lines

#### pairofstrings

Summary
I can find whether the given pair of straight lines are in parallel or is intersecting.
I am comfortable with word problems on straight lines.
Hello,

I want to see word problems on pair of straight lines to know the real-time applications.
I want to find out what it means if a straight line intersects/is parallel to other straight line.

Thanks!

#### phinds

Gold Member
Do you know how to determine that slope of a straight line? Could two lines with the same slope intersect? Could two lines with different slopes NOT intersect?

#### pairofstrings

Hi,
Do you know how to determine that slope of a straight line?
I know how to find slope of a straight line that looks like this: y = mx.
Could two lines with the same slope intersect?
No. They will extend till infinity - parallely.
Could two lines with different slopes NOT intersect?
Yes, they can intersect somewhere when I can extend the line till infinity.

If I have two lines given like this: then what real-time problem I can solve with it?

#### symbolipoint

Homework Helper
Education Advisor
Gold Member
then what real-time problem I can solve with it?
You are basically asking, "when will I use this?".
The answer is found only in too many possible applications, and depends on what you find when you find them. Otherwise, check the examples of application problems in your textbook.

y=mx+b, z=Mx+c
If m=M, and if you would plot y and z on the same vertical axis, these lines will be parallel and would not intersect.

#### Mark44

Mentor
Could two lines with different slopes NOT intersect?
Yes, they can intersect somewhere when I can extend the line till infinity.
It's not possible to "extend the line till infinity" in any practical sense.
If I have two lines given like this:
View attachment 246899
then what real-time problem I can solve with it?
If all you are given is an image of two line segments, there's not much you can do. If the slopes of the lines are just slightly different, they will intersect somewhere (at some finite point).

You asked about "real-time" problems, but you probably mean "real-life" problems. Just about any algebra textbook will have lots of applications of linear equations, as would numerous web sites, using a search string of, say, "linear equations applied problems".

Thread closed.

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