Question

ME AJUDA POR FAVOR!

Determine as raízes da equaçao
1)x²-x-12=0
2)x²+2x-15=0

Answer 1

Resolvendo por Bháskara.

$x = \dfrac{-b \pm \sqrt{b^2 -4*a*c}}{2*a}$

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1)

$x^2 - x - 12 = 0$

a=1, b=−1, c=−12

Δ=b²−4ac
Δ=(−1)²−4*(1)*(−12)
Δ=1+48
Δ=49

$x = \dfrac{-b \pm \sqrt{\triangle}}{2*a}$

$x = \dfrac{-(-1) \pm \sqrt{49}}{2*1} \\ \\ \\ x = \dfrac{1 \pm 7}{2} \\ \\ \\ x' = \dfrac{1 + 7}{2} \\ \\ \\ x' = \dfrac{8}{2} \\ \\ \\ x' = 4 \\ \\ \\ x'' = \dfrac{1 - 7}{2} \\ \\ \\ x'' = \dfrac{-6}{2} \\ \\ \\ x'' = -3$

S = {4, -3}

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2)

$x^2 + 2x - 15 = 0$

a=1, b=2, c=−15

Δ=b²−4ac
Δ=(2)²−4*(1)*(−15)
Δ=4+60
Δ=64

$x = \dfrac{-b \pm \sqrt{\triangle}}{2*a}$

$x = \dfrac{-2 \pm \sqrt{64}}{2*1} \\ \\ \\ x = \dfrac{-2 \pm 8}{2} \\ \\ \\ x' = \dfrac{-2 + 8}{2} \\ \\ \\ x' = \dfrac{6}{2} \\ \\ \\ x' = 3 \\ \\ \\ x'' = \dfrac{-2 - 8}{2} \\ \\ \\ x'' = \dfrac{-10}{2} \\ \\ \\ x'' = -5$

S = {3, -5}