2y/5y cube + 4y square + 6y

here down is the answer

(2y/5y)^3+4y^2+6y

8y^3/125y^3 +16y^2+6y

8/125+16y^2+6y

8/125+16y^2+6y=0

16y^2+6y+8/125=0

it is in the form of quadratic equation

formula :

x=(-b+-square root of b^2-4ac) /2a

here a=16,b=6&c=8/125

x=(-b+-square root of b^2-4ac)/2a

x=(-6+-square root of 36-4.09)/2a here 4.09 came by calculation

x=(-6+-31.91)/2

so

x=(-6+31.91)/2 first (+);

x=25.91/2

x=12.955;

x=(-6-31.91)/2 then(-);

x=-37.91/2

x=-18.955 ;

ans is = 12.955&-18.955;

or