given
[tex] {n}^{2} + {n}^{2} + {n}^{2} [/tex]
for n = -1
substitute them into the equation
[tex] = ( { - 1})^{2} + ( { - 1})^{2} + ( { - 1)}^{2} [/tex]
when you square a negative number, it becomes positive.
because negative×negative = positive
[tex] = 1 + 1 + 1[/tex]
[tex] = 3[/tex]
as final answer
