Question

resolva as equaçães:

${x}^{2} - 25 = 0$
${x}^{2} - \frac{81}{4?} = 0$


alguém???...help!!^-^♡♡♡...please?...​

Answer 1

x² - 25 = 0

x² = 0 + 25

x² = 25

x= ± √25

x= ± 5

S= ( 5 , - 5)

x² - 81/4 = 0

x² = 81/4

x= ± √(81/4)

x= ± 9/2

S= ( 9/2 , - 9/2)

Answer 2

Resposta:

$a) \: S = \{ - 5; \: 5 \} \\ b) \: S = \{ - \frac{9}{2} ; \: \frac{9}{2} \}$

Explicação passo-a-passo:

$a) \: {x}^{2} - 25 = 0 \\ {x}^{2} = 0 + 25 \\ {x}^{2} = 25 \\ x = \pm \sqrt{25} \\ x = \pm \: 5$

$b) \: {x}^{2} - \frac{81}{4} = 0 \\ 4 {x}^{2} - 81 = 0 \\ 4 {x}^{2} = 0 + 81 \\ 4 {x}^{2} = 81 \\ {x}^{2} = \frac{81}{4} \\ x = \pm \sqrt{ \frac{81}{4} } \\ x = \pm \: \frac{9}{2}$