<span>2+cos2x=2</span><span>sin</span><span>x</span>
-sin^2(x)+cos^2(x)+2=2 sin(x)
cos(2x)-2 sin(x)=-2
1)x²-100x=0,x(x-100)=0, x1=0,x2=100
2)9/25x³-x=0, x(9/25x²-1)=0,x((3x/5)²-1²)=0,x(3x/5+1)(3x/5-1)=0
x1=0,x2=-5/3,x3=5/3
3)25y²+20y+4=0,(5y+2)(5y+2)=0, y=-2/5
4)36x²+25=60x,36x²ˇ-60x+25=0,(6x-5)²=0,x=5/6
Сомневаюсь,что условие дано верно..<span />