How can I solve this?

[Sarah.N]

Hi.
Is there anybody who can help me solve this question?

" if xy=-1 , x+y =2 , then 15x^2+ 9y^2= ? ( |x|>|y| )"

 

[Deleted member 4993]

Hi.
Is there anybody who can help me solve this question?

" if xy=-1 , x+y =2 , then 15x^2+ 9y^2= ? ( |x|>|y| )"

If I were to solve this problem:

I would first solve for x & y, from:

x * y = -1...................and​

​

x + y = 2 ...................using substitution method.​

Please show us what you have tried and exactly where you are stuck.

Please follow the rules of posting in this forum, as enunciated at:

READ BEFORE POSTING​

Please share your work/thoughts about this problem.

 

[Sarah.N]

Thanks but I finally solved it.
This is how I solved it:

 

[Deleted member 4993]

Thanks but I finally solved it.
This is how I solved it:

View attachment 23139

Nice work - very clever...