Question

So I'm going to see if I can figure this one out, don't help yet. :) Just tell me if I'm going in the right direction. :)

Which system of linear equations has no solution?

A. 2x − y = −1
2x + y = 2

B. 4x − y = 3
3x − 2y = 3

C. −2x + 4y = −16
4x − 2y = −1

D. 2x − y = −1
−2x + y = −1

B AND D ARE RULED OUT!

@ikatouni @mathmate

Answer 1

@ikatouni @mathmate

Answer 2

@mathmate

Answer 3

Can you tell me why B and D are ruled out?

Answer 4

I'm looking for one that's not equal (or coefficient)
B and D look like they are. They have the same answers.
@mathmate
:)

Answer 5

You're looking for two parallel lines that are NOT equivalent.

Answer 6

For example, in A, look at the left-hand side.
No matter what you multiply which one, you cannot make the equations equal, so ruled out.

Answer 7

If you can do some multiplications and match the left-hand side, then check the right hand side. If the two equations are identical on the left-hand side, but are different on the right, that's the guy you're looking for.

Answer 8

I think it's D.

Answer 9

@mathmate

Answer 10

Yup

Answer 11

hihihi.. It's so nonsense when a 61smartscore guy check the stuff of a 75smartscore Asker.
Whatsoever, I think d is the correct answer

Answer 12

That is correct.
If you multiply the second equation by -1.
the left-hand side will be equal, but the right-hand sides are -1 and +1, so they are parallel and NOT coincident.
Good job!

Answer 13

@OOOPS It may sound funny, but it happens a lot in real life!
In any case, the score means someone have worked a lot, and have a lot of experience in some field. We can always learn something every day, right?

Answer 14

yup, yup yup.... hihihihi...

Answer 15

Yay! Thanks! :)

Answer 16

You're welcome! :)

Answer 17

@Mertsj Check this one to? :) D?

Answer 18

@Mertsj

Answer 19

@Marco,Phillip @Hero D?