Matrices - Invariant Points

I get the books answer. Post some working, and we can see what you're doing.

Kind of hard to post the matrices, but I multiply the matrix (-0.6,0.8|0.8,0.6) with (x|y), ending up with two equations:

i) 0 = -1.6x + 0.8y
ii) 0 = 0.8x - 0.4y

The lines are equivalent, so I end up with points along the line where x = 2y.

I have missed a few lessons on this, so I may be doing something foolish

I'll use the second one:

0 = 0.8x - 0.4y

0.4y = 0.8x

Divide by 0.4

y = 2x

Dear lord...

I don't know how I just equated 0.4y = 0.8x with x = 2y...

It happens. Everyone's done something like that, or even sillier.

Thanks for the condolences, but I feel pretty damn foolish right now