Question

допоможіть будь ласка​

Answer 1

$6. \: \: \: \: \: 4.7 \times {10}^{ - 4} = 4.7 \times \frac{1}{ {10}^{4} } = 4.7 \times \frac{1}{10000} = 4.7 \times 0.0001 = 0.00047$

Ответ: в)

$7. \: \: \: \: \: \frac{2}{x} = x - 1$

$2 = x(x - 1) \: \: \: \: \: \: \: \: \: \: \: \: \: \: \: \: \\ {x}^{2} - x = 2 \: \: \: \: \: \: \: \: \: \: \: \: \: \: \: \: \: \: \: \: \: \\ {x}^{2} - x - 2 = 0 \: \: \: \: \: \: \: \: \: \: \: \: \: \\ x1 + x2 = - ( - 1) = 1 \\ x1 \times x2 = - 2 \: \: \: \: \: \: \: \: \: \: \: \: \: \: \\ x1 = 2 \: \: \: \: \: \: x2 = - 1 \: \: \: \: \:$

$8. \: \: \: \: \:$

$a) \: \: \: \: \: \frac{ {8}^{ - 2} \times {4}^{ - 2} }{ {2}^{0} \times {64}^{ - 1} } = \frac{ {2}^{0} \times {64}^{1} }{ {8}^{2} \times {4}^{2} } = \frac{1 \times 64}{64 \times 16} = \frac{1}{16}$

$b) \: \: \: \: \: \frac{ {21}^{5} \times {3}^{ - 7} }{ {63}^{ - 2} \times {7}^{8} } = \frac{ {21}^{5} \times {63}^{2} }{ {3}^{7} \times {7}^{8} } = \frac{ {7}^{5} \times {3}^{5} \times {7}^{2} \times { ({3}^{2}) }^{2} }{ {3}^{7} \times {7}^{8} } = \frac{ {7}^{7} \times {3}^{9} }{ {3}^{7} \times {7}^{8} } = \frac{ {3}^{2} }{7} = \frac{9}{7} = 1 \frac{2}{7}$