Explicação passo-a-passo:
[tex]a)x {}^{2} - 9 = 0 \\ x {}^{2} = 9 \\ x = \sqrt{9} \\ x = 3 \\ s = (3 \: \: \: - 3) \\ \\ b) 4x {}^{2} - 36 = 0 \\ 4x {}^{2} = 36 \\ x {}^{2} = \frac{36}{4} \\ x {}^{2} = 9 \\ x = \sqrt{9} \\ x = 3 \\ s = (3 \: \: \: - 3) \\ \\ c)16x {}^{2} - 64 = 0 \\ 16x {}^{2} = 64 \\ x {}^{2} = \frac{64}{16} \\ x {}^{2} = 4 \\ x = \sqrt{4} \\ x = 2 \\ s = (2 \: \: \: - 2) \\ \\ d) x {}^{2} - 4 = 0 \\ x {}^{2} = 4 \\ x = \sqrt{4} \\ x = 2 \\ s = (2 \: \: \: - 2) [/tex]
