We can draw the rectangle QRST as:
The two diagonals of a rectangle will have the same length, so we can write:
[tex]\begin{gathered} QS=RT \\ 5x+12=6x-2 \\ 5x-6x=-2-12 \\ -x=-14 \\ x=14 \end{gathered}[/tex]With the value of x, we can calculate the length of the diagonal:
[tex]QS=5x+12=5\cdot14+12=70+12=82[/tex]Answer: the lengths of the diagonals QS and RT is 82.
