Question

ME AJUDEM POR FAVOR !!​

Answer 1

$1) \\ \\ a) \\ {x}^{2} - 64 = 0 \\ {x}^{2} = 64 \\ x = \sqrt{64} \\ x = 8 \: ou \: - 8\\ \\ b) \\ 4 {x}^{2} - 46 = 0 \\ 4 {x}^{2} = 46 \: \: \: ( \div 4) \\ {x}^{2} = 11.5 \\ x = \sqrt{11.5} \\ \\ c) \\ 3 {x}^{2} + 25 = 0 \\ 3 {x}^{2} = - 25 \\ {x}^{2} = \frac{ - 25}{3} \\ x = \sqrt{ \frac{ - 25}{3} } \\ x = \: impossivel$

$3) \\ \\ a) \\ {x }^{2} + x - 12 = 0 \\ \\ delta = {b}^{2} - 4ac \\ delta = {1}^{2} - 4(1)( - 12) \\ delta = 1 + 48 \\ delta = 49 \\ \\ \frac{ - b + ou - \sqrt{delta} }{2a} \\ \\ \frac{ - 1 + 7}{2} = \frac{6}{2} = 3 \\ ou \\ \frac{ - 1 - 7}{2} = \frac{ - 8}{2} = - 4 \\ \\ b) \\ - {x}^{2} + 14x - 49 = 0 \: \: \: ( \times - 1) \\ {x}^{2} - 14x + 49 = 0 \\ \\ delta = ( - 14 {)}^{2} - 4(1)(49) \\ delta = 196 - 196 \\ delta = 0 \\ \\ \frac{ - ( - 14) + 0}{2} = \frac{14}{2} = 7 \\ \\ c) \\ {x}^{2} - 12x + 5 = 0 \\ \\ delta = ( - 12 {)}^{2} - 4(1)(5) \\ delta = 144 - 20 \\ delta = 124 \\ \\ x = irracional$

$2) \\ \\ a) \\ {x}^{2} - 8x = 0 \\ x(x - 8) = 0 \\ x = 0 \\ ou \\ x - 8 = 0 \\ x = 8 \\ \\ b) \\ 6 {x}^{2} + 18x = 0 \\ 6x(x + 3) = 0 \\ x = 0 \\ ou \\ x + 3 = 0 \\ x = - 3 \\ \\ c) \\ {x}^{2} - 25x = 0 \\ x(x - 25) = 0 \\ x = 0 \\ ou \\ x - 25 = 0 \\ x = 25$