b: \(5^2+4^2=25+16=41\)
\(\left(5+4\right)^2=9^2=81\)
mà 41<81
nên \(5^2+4^2< \left(5+4\right)^2\)
c: \(13^2-8^2=169-64=105\)
\(\left(13-8\right)^2=5^2=25\)
mà 105>25
nên \(13^2-8^2>\left(13-8\right)^2\)
\(b,\)\(5^2+4^2\)\(=25+16\) \(=41\)
\(\left(5+4\right)^2=9^2=81\)
\(mà\) \(41< 81\)
\(nên\) \(5^2+4^2< \left(5+4\right)^2\)