Question

Quais são as raízes da equação x2-3x-4=0?
a)S={1 e 7}
b)S={9 e 14}
c)S={2 e 8}
d)S={-1 e 4}

Answer 1

x²-3x-4=0 A=1 B=-3 C=-4

Delta=b²-4•a•c

Delta=(-3)²-4•1•(-4)

Delta=9+16

Delta=25

Bháskara: -b+-√Delta/2•a

Bháskara: 3+-√25/2•1

Bháskara: 3+-5/2

X'=3+5/2

X'=8/2

X'=4

X"=3-5/2

X"=-2/2

X"=-1

S= {4, -1}

Resposta: D)