Question

9. Quais destes números são raízes da
equação x2 - 5x + 6 = 0?
0 1 2 3 4

Answer 1

$\sf \: x {}^{2} - 5x + 6 = 0 \\ \sf \: x {}^{2} - 5x = - 6 \\ \sf \: x {}^{2} - 5x + \Bigg( \frac{5}{2} \Bigg) {}^{2} = - 6\Bigg( \frac{5}{2} \Bigg) {}^{2} \\ \sf \: \Bigg(x - \frac{5}{2} \Bigg) {}^{2} = - 6 + \Bigg( \frac{5}{2} \Bigg) {}^{2} \\ \sf \:\Bigg(x - \frac{5}{2} \Bigg) {}^{2} = \frac{1}{4} \\ \sf \: x = 2 \\ \sf \: x = 3$

Att: Nerd1990