=50*2sin(arccos(-0,8))cos(arccos(-0,8))=100sin(π-arcsin(sqrt(1-(-0,8)^2)))*(-0,8)=-80sin(arcsin(sqrt(0,36)))=-80sin(arcsin(0,6))=-80*0,6=-48
ОДЗ: 4х+3≠0, х≠-075; ((3х+5)/(4х+3)) >0: х∈(-∞; /5/3)∪(-3/4;∞).
х²-2х-3=0 или lg((3x+5)/(4x+3))=0.
х1=3; х2=-1. или (3х+5)/(4х+3)=1; 3х+5=4х+3: х3=2.
х1+х2+х3=3-1+2=4.
Ответ:4.