Question

Решите срочно

37² - 13²
_______
72² - 12²
и еще

100² - 60²
________
70² - 90²

Answer 1

$\frac{ {37}^{2} - {13}^{2} }{ {72}^{2} - {12}^{2} } = \frac{(37 - 13)( 3 7 + 13)}{72 - 12)(72 + 12)} = \frac{24 \times 50}{60 \times 84} = \frac{1200}{5040} = \frac{5}{21} = 0,238095$
$\frac{ {100}^{2} - {60}^{2} }{ {70}^{2} - {90 =}^{2} } = \frac{ {10}^{4} - ( {6 \times 10)}^{2} }{(70 - 90)(70 + 90)} = \frac{ {10}^{4} - {6}^{2} \times {10}^{2} }{ - 20 \times 160} = \frac{( {10}^{2} - {6}^{2}) \times {10}^{2} }{ - 3200} = \frac{64 \times 100}{ - 3200} = - 2$