Question

If r = 3t and r-t = 8, then r^2 + t^2 = ?

Answer 1

\[r=3t\\
r-t=8~\Rightarrow~r=8+t\]
So you have the equation
\[3t=8+t\\
2t=8\\
t=4\]
Solve for \(r\), then plug in \(r,t\) into \(r^2+t^2\).

Answer 2

thanks