Question

determine as funções de:
y= -x² + 12x -20

Answer 1

Calcule o Delta:
Delta=b² -4.a.c
Delta=12² - 4.(-1).(-20)
Delta=144-80
Delta=64

Calcula o valor de X' e X"
X'=-12+8/2.(-1)
X'=-12+8/-2
X'=-4/-2
X'=2

X"=-12-8/-2
x"=-20/-2
x"=10

S={2,10)

Answer 2

-x²+12x-20         multiplica por (-1)
x²-12x+20=0
Delta=b²-4.a.c
delta=144-80
delta=64

x=-b+-raiz de 64/-2
x=-12+-8/-2
x'=-12+8/-2 = -4/-2 = +2
x''=-12-8/-2 = -20/-2 = +10

S={+2,10}

y=-x²+12x-20
y=-4+24-20
y=0

y=-x²+12x-20
y=-100+120-20
y=0

ta certo 
Espero ter ajudado você!!!Bons estudos Kmila!