Question

1) Resolva as seguintes equações incompletas do segundo grau

Answer 1

Resposta:

$a) {x}^{2} - 49 = 0 \\ {x}^{2} = 49 \\ x = \sqrt{49} \\ x = 7 \: \: \: \: \: x = - 7$

$b) {2x}^{2} - 50 = 0 \\ {2x}^{2} = 50 \\ {x}^{2} = \frac{50}{2} \\ x {}^{2} = 25 \\ x = \sqrt{25} \\ x = 5 \: \: \: \: \: x = - 5$

$c) {4x}^{2} = 36 \\ {x}^{2} = \frac{36}{4} \\ {x}^{2} = 9 \\ x = \sqrt{9} \\ x = 3 \: \: \: \: \: x = - 3$

$d) {7x}^{2} - 7 = 0 \\ 7 {x}^{2} = 7 \\ {x}^{2} = \frac{7}{7} \\ {x}^{2} = 1 \\ x = \sqrt{1} \\ x = 1 \: \: \: \: \: x = - 1$

$e) {5x}^{2} - 15 = 0 \\ {5x}^{2} = 15 \\ {x}^{2} = \frac{15}{5} \\ {x}^{2} = 3 \\ x = \sqrt{3} \: \: \: \: \: x = - \sqrt{3}$

$f) {4x}^{2} - 49 = 0 \\ {4x}^{2} = 49 \\ {x}^{2} = \frac{49}{4} \\ x = \sqrt{ \frac{49}{4} } \\ x = \frac{7}{2} \: \: \: \: \: x = - \frac{7}{2} \\ ou\\ x = 3.5 \: \: \: \: \: x = - 3.5$

$g) {x}^{2} = 1 \\ x = \sqrt{1} \\ x = 1 \: \: \: \: \: x = - 1$

$h) {5x}^{2} + 20 = 0 \\ {5x}^{2} = - 20 \\ {x}^{2} = \frac{ - 20}{5} \\ {x}^{2} = - 4 \\ x = \sqrt{ - 4} \\ nao \: possui \: raizes \: reais$