# What Is x and y?

Hello, Everyone! How  R U?

I want to give U a math problem, high school algebra or college freshman algera level.

Let x and y be two unknown variables.

Question : If

x+y=7

x-y=3,

then,

what is x and y?

Solution:

x=___

y=___

Hint: solve it as system of linear equations.

If  U have forgotten about this level of math, please think about the question by guess: how many ways to have two numbers sum as 7, then find the pair of numbers with difference as 3.

for example,  7=7+0=6+1=5+2=4+3=3+4=2+5=1+6=0+7, I have told you 8 ways of sum to 7.

Solutions: x=5, y=2.

check:

5+2=7,

5-2=3. Thus solution is correct.

There are many ways of doing it, Doraz commented exactly how to solve it graphically, mathematically, or using methods of substitutions, cancellations. We can also solve it using graphing Ti-83 calculator…Any way. I give this question which is mediate hard, thus I prefer not to make it too abstract to majority readers. Let me know if you have questions!

Outstanding job, everyone who joined the fun! 15 of U did wonderfully in math computation on this one.

## 31 thoughts on “What Is x and y?”

1. tonydowning says:

x=5 and y=2

Q: what is the sum of all the whole numbers from 1 to 100?

A: well, there are 50 pairs in that range, and each pair = 101 (for example 1+100=101, 2+99=101, 3+98=101, etc.) So, the answer is: 50 pairs x 101=5050!

thanks Jingle, talk to U later!

2. Corve DaCosta says:

x = 5
y = 2

3. william says:

hehehe welcome back to math day lol, x=5 y=2 now that’s not too hard for billy boy lol, have a great sunshine day xx

4. justmeshakira says:

Dearest Jingle,
So happy to see you up today!

x+y=7
x-y=3,

then,
what is x and y?

x is 5
and
y is 2

I think I can do Maths now.lol

Have you a gorgeous day, love!

hugs
shakira

5. CottageGirl says:

x=5, y=2
If you can believe it … We are now teaching an algebraic based math series and that would be one of our problems in … First Grade!
Hard to teach 7 year old this concept … Hard for them to learn!

6. ishabelle says:

x is 5 y is 2… right? *wink*

7. brian miller says:

hope you are having a great day jingle!

8. THE BEATY says:

ok Jingle my work is as fallows
x+y=7
x-y=3
Lets start by adding x to both sides of the second equation.
this means x=y+3
after that you substitute this equation for y in the first equation
this means that 2y+3=7
from their you subtract 3 from both sides and devide by 2 giving the answer
x=5
y=2

great problem Jingle. Thats what I’m doing in my math class.

9. Sunny says:

Ha! I think I got it! x=5 and y=2

I thought that my bedrest had completely melted my brain, but apparently there is something small left in there, doing some work. 🙂

10. blissbait says:

Wow! You are one of those brilliant math-minded beings!!! I bow to You and smile and say my brain will explode if I dive into this. I’ve got a circus mind and numbers never got the memo to come on over and join in! I SO admire people like You! Thank YOu for the kindness You left in my room!!! Cheers and Namaste. 🙂

11. laurenmichelleotheim says:

Hee hee, my roommate is a math major and I just asked her what the answer was…. 🙂

12. thisrainykitten says:

Hi Jingle,

Are you kidding with this???? LOL! This is one of the reasons why I chose art school!! I look at equations like this and I want to draw beautiful, fluid, calligraphic lines all over them. What is the answer, like a 2 or something? (Not that I tried to figure it out!!!) Love, Lisa

13. artiste7 says:

I had to ask my best friend who is a math head. This just makes my brain bleed. She is figuring out now. I’ll keep the answer till tomorrow.

14. Doraz says:

The system has a unique solution:
x = 5
y = 2

It can be found various ways
-The point at which the two lines intersect
-Creating an augmented matrix and using Gaussian elimination (row echelon form) or Gauss-Jordan elimination (reduced row echelon form)
– Creating a Matrix A=[1,1;1-1], vector column b [7;3], then taking the inverse of A and multiplying it by vector column b.
Note: to find the inverse of a matrix, take (1/determinant(A))*adjoint(A).

15. justmeshakira says:

Lol, Jingle…. I am so sorry that I cannot play.
One of the blogger I know, just passed away.
I just knew, will check with you when you post the answer.

hugs
shakira

16. Doraz says:

Try this one, it’s also intermediate algebra:

Determine the solution set to
5x-6y+z = 4
2x-3y+z = 1
4x-3y-z = 5

17. Collin says:

x=5 and y=2

18. Sandra says:

x+y=7
or, x=7-y
Putting the value of x in the equation x-y=3 we get:
7-y-y=3
or, 7-2y=3
or,-2y=-3-7
or, -2y=-4
or, y=2

hence x=5 and y=2

Am i r8 Jingle?

19. Pamela says:

x=5
y=2 😛

20. datsme says:

x=5, y=2 🙂

21. Yousei Hime says:

x=5, y=2 and Doraz’s is x=1, y=0, z=-1 Fun! My dad would be proud of me. 😀

1. Doraz says:

Yousei Hime:

You specified one of the infinite solutions.

S = {(2+t, 1+t, t) : t∈ℝ}

Do you want me to work it out?

1. Yousei Hime says:

I thought you were doing algrebra, not calculus or differential and stuff. Ugh. Sure, ‘splain it to me. I miss my dad enough to listen to another lesson. (He used to catch me on my way to watch a tv show and say, “Come here. Let me show this.” Of course, I missed the show.) 😀

2. jingle says:

Yousei,

I am impressed by your effort to do the extra math problem…
thumbs up!
😉

22. Amy says:

okay I am not one for Math. I finally got it in college and I look at this an I am like uh no way.. Have a great day.

23. kathy says:

Pengsan.Mine math are enam pening.

24. Abcd says:

Lol…Jingle i loved this. Mathematic teaching life. THANK YOU for this post.

25. Mama Zen says:

x=5
y=2

Now, I need a nap!

26. jingle says:

solution for the math problem is out!
thank U all for trying.
15 of U did absolutely wonderful and correctly…
amazing results!
😉

27. sunshineonthesewertop says:

I really like this. I absolutely agree, the fire of creativity runs deep.
Nice piece.

28. sunshineonthesewertop says:

That last comment was intended for the poem you posted before this. My apologies.
I am not a math fan, what so ever. My brain does not work that way.
Happy Wednesday, almost Thursday to you!