ANSWER
[tex]x=16;x=26[/tex]EXPLANATION
We want to solve the equation:
[tex](x-21)^2=25[/tex]To do this, find the square root of both sides of the equation:
[tex]\sqrt[]{(x-21)^2}=\sqrt[]{25}[/tex]This will yield two results:
[tex]\begin{gathered} \Rightarrow x-21=5 \\ \Rightarrow x-21=-5 \end{gathered}[/tex]Solving the two equations, we have:
[tex]\begin{gathered} \Rightarrow x=5+21 \\ x=26 \\ \Rightarrow x=-5+21 \\ x=16 \end{gathered}[/tex]The solutions are:
[tex]x=16,x=26[/tex]