a) y^2-y+5y-10-6y-30

    y^2-2y-40

b) (y+5)(y-2-6)

    (Y+5)(y-8)

c) (y+5)(y-8)=0

 donc

y+5=0

y=-5    ou alors  

y-8=0

y=8

donc S{-5 ; 8 }

1a) A = (y+5)(y-2)-6(y+5)

A = y²+5y-2y-10-6y-30

A = y²-3y-40

b) A = (y+5)(y-2-6)

A = (y+5)(y-8)

c/ y+5 = 0  donc y = - 5

y-8 = 0  y = 8

donc la solution est y = -5 ou 8