Help please.

Cd is the perpendicular bisector of both xy and st, and cy=20. find xy.

To diagonalize an nxn matrix a means to find an invertible matrix p and a diagonal matrix d such that a pdp d p ap or [1 3 dh epap 3 let a=-3 -5 -3 3 3 1 step 1: find the eigenvalues of matrix a "2's" step 2: find the corresponding eigenvectors of a step 3: createp from eigenvectors in step 2 step 4 create d with matching eigenvalues.

At the movie theatre, child admission is $5.20 and adult admission is $9.70. on sunday three time as many adult tickets as child tickets were sold, for a total sales of $788.90. how many child tickets were sold that day?