Х+2 = 4-2х
3х=2
х=2/3
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1). 10*0,5*a*a^2*b^3*b*b^3=5a^3b^7; 2) x*x^5*x^3*y*y^3*y^8=x^9y^12.
6-18с+21b-35c+44-8b=-53c+13b+50
4sin(20°)sin(40°)sin(60°)sin(80°)=2sin(20°)sin(40°)√3*sin(80°=(cos(-20°)-cos(60°))√3*sin(80°)=(cos(20°)-1/2)√3*sin(80°)=√3/2*(2sin(100°)+√3)/(2)-(√3*sin(80°))/2=2√3sin(100°)+3-2√3sin(80°)=0,75