Which point is on the line that passes through point z and is perpendicular to line ab?

I've never been good at math he told he loves but he keeps cheating on me, so it ain't adding up sis

Solve for x and y: 217x + 131y = 913; 131x + 217y = 827

Elizabeth claims that the fourth root of 2 can be expressed as 2^m since (2^m)^n = 2. find the values of m and n for the case where elizabeth's claim is true.