a)4x+12-2|x+3|=2x+10+2x
-2|x+3|=-2
|x+3|=1
x+3=1. x=-2
x+3=-1, x=-4
b) [tex] x^ {2} -6x+9-3x+30 \leq x^{2}-16+1 \\ -9x \leq -54
[/tex]
[tex]x \geq 6[/tex]
2)T=F+28
T+x=3(F+x) F+28+x=3F+3x, 2F+2x=28, F+x=14
T-x=15(F-x) F+28-x=15F-15x, 14F-14x=28, F-x=2
2F=16, F=8,T=36