Question

Решите систему уравнений
X²+y²=85
Y-x=7

9y+x²=9
x-y=-1

Answer 1

$x { }^{2} + y {}^{2} = 85$

$(r {}^{2} \times cos(ө)) {}^{2} + (r \times sin(ө)) {}^{2} = 85$

$r {}^{2} \times cos(ө) {}^{2} + r \times sin(ө) {}^{2} = 85$

$r {}^{2} \times (cos(ө) {}^{2} + sin(ө) {}^{2} ) = 85$

$r {}^{2} \times 1 = 85$

$r {}^{2} = 85$

$r = + \sqrt[]{85}$

$r = - \sqrt{85}$

$r = \sqrt{85}$

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$y - x = 7$

$- x + y = 7$

$x - y = - 7$

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$9y + x {}^{2} = 9$

$9y = 9 - x {}^{2}$

$y = 1 - \frac{1}{9} x {}^{2}$

$y = 1 - \frac{1}{9} x {}^{2} ,ХЄR$

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$x - y = - 1$

$x - y + 1 = - 1 + 1$

$x - y + 1 = 0$