Resposta:
a) x² – 49 = 0
(x – 7)(x + 7) = 0
x = 7 ou x = -7
b) x² = 1
(x – 1)(x + 1) = 0
x = 1 ou x = -1
c) 2x² – 50 = 0
2(x² – 25) = 0
2(x – 5)(x + 5) = 0
x = 5 ou x = -5
d) 7x² – 7 = 0
7(x² – 1) = 0
7(x – 1)(x + 1) = 0
x = 1 ou x = -1
e) 4x² = 36
4(x² – 9) = 0
4(x – 3)(x + 3) = 0
x = 3 ou x = -3
f) 5x² – 15 = 0
5(x² – 3) = 0
5(x – √3)(x + √3) = 0
x = √3 ou x = -√3