b: \(f\left(-1\right)=-\sqrt{2}\)
=>\(A\left(-1;-\sqrt{2}\right)\)
\(f\left(1\right)=\sqrt{2}\)
=>\(B\left(1;\sqrt{2}\right)\)
\(f\left(2\right)=2\sqrt{2}\)
=>\(C\left(2;2\sqrt{2}\right)\)
c; \(OA=\sqrt{\left(-1\right)^2+\left(-\sqrt{2}\right)^2}=\sqrt{3}\)
\(OB=\sqrt{1^2+2}=\sqrt{3}\)
\(OC=\sqrt{2^2+8}=2\sqrt{3}\)