Question

a ) x²-3x-4=0
b ) x²-x-12=0
c ) x²-4x-5=0
d ) -3x²+18-15=0
e ) 2x²+8-24=0​

Answer 1

Resposta:

A) x²-3x-4=0

A=1;B=-3;C=-4

Δ=b²-4ac

Δ=(-3)²-4×(1)×(-4)

Δ=9+16

Δ=25

x=-b±√Δ/2a

x=-(-3)±√25/2

x=3±5/2

• x=3+5/2=4

• x=3-5/2=-1
• S={4,-1}

B)x²-x-12=0

A=1,B=-1,C=-12

Δ=b²-4ac

Δ=(-1)²-4×(1)×(-12)

Δ=1+48

Δ=49

x=-b±√Δ/2a

x=-(-1)±√49/2

x=1±7/2

x=1+7/2=4

x=1-7/2=-3

S={4,-3}

c)x²-4x-5=0

A=1;B=-4;C=-5

Δ=b²-4ac

Δ=(-4)²-4×(1)×(-5)

Δ=16+20

Δ=36

x=-b±√Δ/2a

x=-(-4)±√36/2

x=4±6/2

x=4+6/2=5

x=4-6/2=-1

S={5,-1}

D) -3x²+18-15=0

A=-3,B=18,C=-15

Δ=b²-4ac

Δ=18²-4×(-3)×(-15)

Δ=324-180

Δ=144

x=-b±√Δ/2a

x=-18±√144/2×(-3)

x=-18±12/-6

x=-18+12/-6=1

=-18-12/-6=5

S=[1;5}

E) 2X²+8-24=0

A=2;B=8;C=-24

Δ=b²-4ac

Δ=8²-4×2×(-24)

Δ=64+192

Δ=256

x=-b±√Δ/2a

x=-8±√256/2×2

x=-8±12/4

x=-8+12/4=1

x=-8-12/4=-5

S={1;-5}

Explicação passo a passo:

Boa sorte   Espero ter ajudado!