Answer:
See the explanation.
Step-by-step explanation:
If a triangle is a right triangle, then it should follow pythagoras theorem.
So sum of squares of two sides is equal to the square of the third longest side.
[tex](x^{2} -1 )^{2} = x^{4} - 2 x^{2} + 1[/tex]
[tex](x^{2} +1 )^{2} = x^{4} + 2 x^{2} + 1[/tex]
[tex](2x)^{2} = 4x^{2}[/tex]
Adding the first and third equation we get the second equation.
So it follows Pythagoras theorem.
Hence it is a right triangle with [tex]x^{2} + 1[/tex] as the hypotenuse.