Answer :
[tex](5j^2-3j+4)-(8j^2+2)[/tex]
where a j is powered 2, the result is -1 , then replace and simplify the brackets
[tex]\begin{gathered} (5(-1)-3j+4)-(8(-1)+2) \\ (-5-3j+4)-(-8+2) \\ -5-3j+4+8-2 \end{gathered}[/tex]now, group the numbers without j
[tex](-5+4+8-2)-3j[/tex]and operate
[tex]5-3j[/tex]solution is 5-3j