Solving a system of linear equations when the lines are parallel


Find the value of k so that the two given lines will be parallel.


First, put the two equations in standard form

3X - KY = 7

3X - 7 = KY

3X/K -7/K = Y

Now put 2X + 5Y = -1 in standard form too

2X + 1 = -5Y

2X/-5 + 1/-5 = Y

The two equations are now in standard form
y = mx + b

3X/K -7/K = Y

2X/-5 + 1/-5 = Y

They are parallel if the slope are equal.

so they are parallel if 3/K = 2/-5

Cross multiply to get

2K = -15

so K = -15/2

Comments for Solving a system of linear equations when the lines are parallel

Average Rating starstarstarstarstar

Click here to add your own comments

Jan 11, 2014
Most regards,
by: Shah Maqsood Menatpall Akbari

Most regards to you dear sir/madam
I am so happy to be your student in mathematics.
Accept me please that will your kindness.

Thank You

Click here to add your own comments

Join in and write your own page! It's easy to do. How? Simply click here to return to System of linear equations.

Recent Articles

  1. Why Multiply before Adding when doing PEMDAS

    Oct 02, 19 04:34 PM

    Why multiply before adding? The common sense behind doing multiplication before addition

    Read More

New math lessons

Your email is safe with us. We will only use it to inform you about new math lessons.

                                 Follow me on Pinterest

K-12 math tests

Everything you need to prepare for an important exam!

K-12 tests, GED math test, basic math tests, geometry tests, algebra tests. 

Real Life Math Skills

Learn about investing money, budgeting your money, paying taxes, mortgage loans, and even the math involved in playing baseball.