Question

PFV PRA HOJE.SOLUCAO COMPLETA DE: x2-4x=-3

Answer 1

Explicação passo-a-passo:

$\sf x^2-4x=-3$

$\sf x^2-4x+3=0$

$\sf \Delta=(-4)^2-4\cdot1\cdot3$

$\sf \Delta=16-12$

$\sf \Delta=4$

$\sf x=\dfrac{-(-4)\pm\sqrt{4}}{2\cdot1}=\dfrac{4\pm2}{2}$

$\sf x'=\dfrac{4+2}{2}~\rightarrow~x'=\dfrac{6}{2}~\rightarrow~\red{x'=3}$

$\sf x"=\dfrac{4-2}{2}~\rightarrow~x"=\dfrac{2}{2}~\rightarrow~\red{x"=1}$

Answer 2

Oie, Td Bom?!

$x {}^{2} - 4x = - 3$

$x {}^{2} - 4x + 3 = 0$

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$a = 1 \: , \: b = - 4 \: , \: c = 3$

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$x = \frac{ - b± \sqrt{b {}^{2} - 4ac } }{2a}$

$x = \frac{ - ( - 4)± \sqrt{( - 4) {}^{2} - 4 \: . \: 1 \: . \: 3} }{2 \: . \: 1}$

$x = \frac{4± \sqrt{16 - 12} }{2}$

$x = \frac{4± \sqrt{4} }{2}$

$x = \frac{4±2}{2}$

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$x = \frac{4 + 2}{2} = \frac{6}{2} = 3$

$x = \frac{4 - 2}{2} = \frac{2}{2} = 1$

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$S= \left \{ x_{1} = 1 \: , \: x_{2} = 3 \right \}$

Att. Makaveli1996