Question

помогите...
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Answer 1

Обозначим x³ = a , y³ = b , тогда

$\left \{ {{a+b=7} \atop {a*b=-8}} \right. \\\\\\\left \{ {{a=7-b} \atop {(7-b)*b=-8}} \right.\\\\\left \{ {{a=7-b} \atop {7b-b^{2}+8=0 }} \right. \\\\\left \{ {{a=7-b} \atop {b^{2}-7b-8=0 }} \right.$

или b = 8 и тогда a = 7 - 8 = - 1

или b = - 1 и тогда a = 7 - (- 1) = 7 + 1 = 8

$\left \{ {{x_{1}^{3} =- 1 } \atop {y_{1}^{3}=8}} \right.\\\\\left \{ {{x_{1} =-1} \atop {y_{1}=2 }} \right.\\\\\left \{ {{x_{2}^{3} =8 } \atop {y_{2}^{3} =-1 }} \right.\\\\\left \{ {{x_{2}=2 } \atop {y_{2} =-1}} \right.$

Ответ: (- 1 ; 2) ; (2 ; - 1)