I'd appreciate your help...

[notgnsatall]

I have no idea how to do the first one...
about the other., I know how to find an inverse matrix but not how to find the value of a to make it inverse..

 

[Dr.Peterson]

I have no idea how to do the first one...
about the other., I know how to find an inverse matrix but not how to find the value of a to make it inverse..


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These are very different questions, so please don't put them in one thread, which just leads to confusion. I'll ignore the second.

For the first, ignore matrices to start. Can you define two variables and write two equations? If not, tell us what you think when you try to write the equations, so we have something to discuss.

 

[HallsofIvy]

For the second problem, there are two different ways you could try.

Do you know how to find the "determinant" of a matrix and how it is connected to the inverse of the matrix?

Do you know how to find the inverse of a matrix? What happens when you try to find the inverse of this matrix? What values of "a" make that impossible?