Question

Решите срочно

37² - 13²
_______
72² - 12²
и еще

100² - 60²
________
70² - 90²

Answer 1

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