gauss elimination with parameters

I'm breaking my head trying to figure out what i'm doing wrong,
i'm support to eliminate the following equations using Gauss elimination system

and i'm suppose to figure out for which a,b (which are Parameters) the system has One solution/Infinit Solutions/No solutions - if there's infint solutions i'm suppose to write the general solution for the system.
now it's all pretty basic in the begining

1    b  1  3
1  2b  1  4 R2->R2-R1
a    1  1  4 R3->R3-aR1

which leads me to

1   b           1  3
0   b           0  1       * i can reach the first value using /:b , i then get y=1/b
0  1-ab   1-a  4-3a

from here i'm puzzled as there's no way to carry on the elimination (if i'm doing it right)
Who is Participating?
d-glitchConnect With a Mentor Commented:
There are three cases to consider:

1st and 2nd    ==>   a = b = 1    ==>  No solutions

1st and 3rd    ==>   a=1  b=0.5  ==>  Infinite solutions

2nd and 3rd   ==>  b=0 (which you found)  ==>  No solutions

I'm pretty sure that all other cases have single solutions.
You are making things too complicated.

What happens if   a = b = 1 ??

What values will make the 1st and 3rd equations wierd??
d3bugg3rAuthor Commented:
I dont see how it's possible, it will give the following result for the 3rs equation:
0 0 0 0 1 which is not possible, not as a solution anyway.
Free Tool: Subnet Calculator

The subnet calculator helps you design networks by taking an IP address and network mask and returning information such as network, broadcast address, and host range.

One of a set of tools we're offering as a way of saying thank you for being a part of the community.

What happens to the 1st and 2nd equations if   a = b = 1 ??
You don't have to solve them, just look at them.

d3bugg3rAuthor Commented:
yes, it works out... but it doesnt for the 3rd so i cannot use those values as answer.
and i have to define if for those two parameters there's uniqe solution, unlimited solutions or no solutions (like if b=0 then 1/0 on the second equation isnt possible)
NovaDenizenConnect With a Mentor Commented:
Whenever you have an equation involving a product like
r * s = t

When t is zero, at least one of r and s must be zero
When t is nonzero, both r and s must be nonzero

Also, whenever you want to eliminate a factor like in
a*b = 1
to get
a = 1/b
You simply cannot do that unless you have proven that b is nonzero.

Question has a verified solution.

Are you are experiencing a similar issue? Get a personalized answer when you ask a related question.

Have a better answer? Share it in a comment.

All Courses

From novice to tech pro — start learning today.