Question

calcule a soma e o produto das raízes das equações: a) 2x2-10x+8=0 e b)2x2+20x+18=0

Answer 1

a)
$2x^2-10x+8=0 \\ a = 2, b= -10, c = 8 \\ \\ \Delta = b^2 - 4ac \\ \Delta = (-10)^2 - 4 \times 2 \times 8 \\ \Delta = 100 - 64 \\ \Delta = 36 \\ \\ x = \frac{-b \pm \sqrt{\Delta} }{2a} \\ x = \frac{-(-10) \pm \sqrt{36} }{2 \times 2} \\ x = \frac{10 \pm 6}{4} \\\\ x' = \frac{10 + 6}{4} = \frac{16}{4} = 4 \\ x'' = \frac{10 - 6}{4} = \frac{4}{4} = 1 \\ \\ 4 \times 1 = 4 \\ 4 + 1 = 5$

b)
$2x^2+20x+18=0 \\ a = 2, b = 20, c = 18 \\ \\ \Delta = b^2 - 4ac \\ \Delta = 20^2 - 4 \times 2 \times 18 \\ \Delta = 400 - 144 \\ \Delta = 256 \\ \\ x = \frac{-b \pm \sqrt{\Delta}}{2a} \\ x = \frac{-20 \pm \sqrt{256}}{2 \times 2} \\ x = \frac{-20 \pm 16}{4} \\ \\ x' = \frac{-20 + 16}{4} = \frac{-4}{4} = -1 \\ x'' = \frac{-20 - 16}{4} = \frac{-36}{4} = -9 \\ \\ -1 + (-9) = -1 -9 = -10 \\ -1 \times (-9) = 9$

Answer 2

Resposta:

Explicação passo-a-passo:

488?x399 89) +78 ×89