Question

Determine as raízes da equação

a) 2x²-3x-5=0

b) 2x²+7x+5=0

c) 5x²-x=0

d) 2x²-2=0


Me ajudem, por favor​

Answer 1

Resposta:

Explicação passo a passo:

$2x^2-3-5=0\\\\\Delta = b^2-4\times a\times c\\\Delta = (-3)^2 - 4\times 2 \times (-5)\\\Delta = 9 +40\\\Delta = 49\\\\x = \frac{-b \pm \sqrt{\Delta}}{2a}\\x = (-3 \pm 7)/4\\\\x' = \frac{-5}{2}\\\\x" = \frac{4}{4} = 1$

$2x^2 + 7x +5=0\\\Delta = 7^2 - 4\times 2\times 5\\\Delta = 49 - 40\\\Delta = 9\\\\ x = \frac{-7 \pm 3}{4}\\\\x' = \frac{-10}{4} = \frac{-5}{2}\\\\x" = \frac{-4}{4} = -1$

$5x^2 -x = 0 \\x(5x-1) = 0\\\\x' = 0\\\\x'' = \frac{1}{5}$

$2x^2 -2 = 0\\2x^2 = 2 \\x^2 = 1 \\x=\pm1$