9⁵·3³/81³=(3²)⁵·3³/(3³)³=3¹⁰·3³/3⁹=3¹³/3⁹=3⁴=81
Приравнивая каждый множитель , к каждому соответствующему
![x_{1}+x_{2}+x_{3}=-\frac{b}{a}\\ x_{1}x_{2}+x_{2}x_{3}+x_{1}x_{3}=\frac{c}{a}\\ -x_{1}x_{2}x_{3}x_{4}=d\\\\ ](https://tex.z-dn.net/?f=x_%7B1%7D%2Bx_%7B2%7D%2Bx_%7B3%7D%3D-%5Cfrac%7Bb%7D%7Ba%7D%5C%5C%0Ax_%7B1%7Dx_%7B2%7D%2Bx_%7B2%7Dx_%7B3%7D%2Bx_%7B1%7Dx_%7B3%7D%3D%5Cfrac%7Bc%7D%7Ba%7D%5C%5C%0A-x_%7B1%7Dx_%7B2%7Dx_%7B3%7Dx_%7B4%7D%3Dd%5C%5C%5C%5C++++%0A)
√4+1/√49/45=3*5/7=15/7
√1/16+3/2/√25/4=7/40
1/4+3/2=7/4*2/5=14/20=7/10
5/2-3/4=7/4
5/2+5/4=15/4
7/4*4/7=1
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Применим формулу разности квадратов:
![{a}^{2} - {b}^{2} = (a - b)(a + b) \\](https://tex.z-dn.net/?f=+%7Ba%7D%5E%7B2%7D++-++%7Bb%7D%5E%7B2%7D++%3D+%28a+-+b%29%28a+%2B+b%29+%5C%5C+)
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![( \: 7 {a}^{2} + 4b)( \: 7 {a}^{2} - 4b) = {(7 {a}^{2} )}^{2} - {(4b)}^{2} = \\ = 49 {a}^{4} - 16 {b}^{2} \\ \\](https://tex.z-dn.net/?f=%28+%5C%3A+7+%7Ba%7D%5E%7B2%7D++%2B+4b%29%28+%5C%3A+7+%7Ba%7D%5E%7B2%7D++-+4b%29+%3D++%7B%287+%7Ba%7D%5E%7B2%7D+%29%7D%5E%7B2%7D++-++%7B%284b%29%7D%5E%7B2%7D++%3D+%5C%5C++%3D+49+%7Ba%7D%5E%7B4%7D++-+16+%7Bb%7D%5E%7B2%7D++%5C%5C++%5C%5C+)