Question

№5 и 6. Заранее спасибо

Answer 1

$5) \frac{ {87}^{2} - {13}^{2} }{ {91}^{2} - 34 \times 91 + {17}^{2} } = \frac{(87 - 13)(87 + 13)}{( {91 - 17)}^{2} } = \\ \frac{74 \times 100}{ {74}^{2} } = \frac{100}{74} = 1 \frac{26}{74} = 1 \frac{13}{37} \\ \\ 6) {x}^{2} - 6x + 9 + 9 - {x }^{2} = {x}^{2} + 4x + 4 - {x}^{2} \\ 4x + 6x = 9 + 9 - 4 \\ 10x = 14 \\ x = 1.4$