Question

ALGUÉM ME AJUDA
PFVVVVVV
!!!!!!!​

Answer 1

${x}^{4} - 10 {x}^{2} + 9 = 0 \\ {x}^{2} = y \\ {y}^{2} - 10y + 9 = 0 \\ delta = { - 10}^{2} - 4(1)(9) \\ delta \: = 100 - 36 \\ delta \: = 64 \\ \:x = \frac{10 + - \sqrt{64} }{2(1)} \\ x1 = \frac{10 + 8}{2} \\ x1 = 9 \\ x2 = \frac{10 - 8}{2} \\ x2 = 1 \\voltando \\ {x}^{2} = y \: \\ {x}^{2} = 9 \\ x = 3 \\ x = - 3 \\ {x}^{2} = 1 \\ x = 1 \\ x = - 1$

ou seja

S = {-3,-1,1,3}

b)

${x}^{4} - 81 = 0 \\ {x}^{4} = 81 \\ \sqrt[4]{81} = x \\ 3 = x$