Can you help me to solve math questions

1)Fill in the blanks:
If tanx=−4 then tan(−x) =.................
If sinx=0.5 then sin(−x) =.....................
If cosx=0.7 then cos(−x)=....................
If tanx=3 then tan(π+x)=.....................

2)Use a half angle formula to fill in the blanks in the identity below:
(cos(3x))^2=.................+........…

tan(-x)= 4
sin(-x)= -0.5
cos(-x)= 0.7
tan(TT+x)= 3.657