2026 PCSS P2 Q9

The first few lines of a number sequence are:

\(\begin{aligned} 1^2+0^2&=1 \\ 2^2+1^2&=5 \\ 3^2+2^2&=13 \\ 4^2+3^2&=25 \end{aligned}\)

1. Write down the 10th line.[1]
2. Write down in the simplest form, the \(n\)th line, in terms of \(n\).[2]
3. One of the lines in the sequence is \(x^2+y^2=2521\).
   Find the values of \(x\) and \(y\).[4]