[tex]5y+1=10y^2\\10y^2-5y-1=0\\D=(-5)^2-4*10*(-1)=25+40=65=\sqrt{65}^2 \\y_1=\frac{5+\sqrt{65} }{20} \\y_2=\frac{5-\sqrt{65} }{20}[/tex]
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P.S. Hello from Russia :^)