(20y^2-55y-15)/(3-y)

Solution for (20y^2-55y-15)/(3-y) equation:

D( y )

3-y = 0

3-y = 0

3-y = 0

3-y = 0 // - 3

-y = -3 // * -1

y = 3

y in (-oo:3) U (3:+oo)

(20*y^2-(55*y)-15)/(3-y) = 0

(20*y^2-55*y-15)/(3-y) = 0

20*y^2-55*y-15 = 0

5*(4*y^2-11*y-3) = 0

4*y^2-11*y-3 = 0

DELTA = (-11)^2-(-3*4*4)

DELTA = 169

DELTA > 0

y = (169^(1/2)+11)/(2*4) or y = (11-169^(1/2))/(2*4)

y = 3 or y = -1/4

5*(y+1/4)*(y-3) = 0

(5*(y+1/4)*(y-3))/(3-y) = 0

( 5 )

5 = 0

y belongs to the empty set

( y+1/4 )

y+1/4 = 0 // - 1/4

y = -1/4

( y-3 )

y-3 = 0 // + 3

y = 3

y in { 3} 

y = -1/4