Question

-2ײ+3×+5=0equacao de2grau
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Answer 1

$-2x^2+3x+5=0$

$a=-2\quad b=3\quad c=5$

$\Delta=b^2-4\cdot a\cdot c$

$\Delta=3^2-4\cdot(-2)\cdot5$

$\Delta=9+40$

$\Delta=49$

$x=\dfrac{-b\pm\sqrt\Delta}{2\cdot a}$

$x=\dfrac{-3\pm\sqrt{49}}{2\cdot(-2) }$

$x=\dfrac{-3\pm7}{-4}\begin{cases}x'=\dfrac{-3+7}{-4}=\dfrac{4}{-4}=-1\\\\x''=\dfrac{-3-7}{-4}=\dfrac{-10}{-4}=\dfrac{5}{2}\end{cases}$

$\red{\boldsymbol{S=\{-1~;~5/2\} }}$

Answer 2

Resposta:

S= {–1, 5/2}

Explicação passo-a-passo:

$- 2x {}^{2} + 3x + 5 = 0$

$a = - 2 \: \: \: \: b = 3 \: \: \: \: \: c = 5$

$delta = b {}^{2} - 4ac$

$delta = 3 {}^{2} - 4. - 2 \times 5 = 9 + 20 = 49$

$\sqrt{49} = 7$

$x1 = \frac{ - 3 + 7}{2. - 2} = \frac{4}{ - 4} = - 1$

$x2 = \frac{ - 3 - 7}{2. - 2} = \frac{ - 10}{ - 4} = \frac{5}{2}$