4.sinπ/6+3tg²π/4+cotgπ/4+2.cosπ/3=4.0,5+3.1²+1+2+0,5=
=2+3+1+0,5=6,5
(sinπ/6=cosπ/3)=0,5 , tgπ/4=cotgπ/4=1)
А)3/4y-5/6y+1,25=0,55
9/12y-10/12y=
0,55-1,25
-1/12y=-0,7
Y=0,7:1/12=7/10*12/1=7/5:6/1=42/5=8,4
Г)1/2x-2,5x+3=1,8
5/10x-4/10x=1,8-3
1/10x=-1,2
X=-12/10:1/10=-12/10*10/1=-12