Question

пожалуйста ????????
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Answer 1

$\displaystyle\left \{ {{7^{2x}+4^{2y+1}=85 } \atop {7^{x}-4^{y}=5}} \right. \\\\\\\displaystyle\left \{ {{7^{2x}+4\cdot4^{2y}=85 } \atop {7^{x}-4^{y}=5}} \right.\\\\\\7^{x}=a, \ a>0 \ ; \ 4^{y}=b, \ b>0\\\\\\\displaystyle\left \{ {{a^{2}+4b^{2} =85 } \atop {a-b=5}} \right.\\\\\\\displaystyle\left \{ {{(b+5)^{2}+4b^{2} =85 } \atop {a=b+5}} \right.\\\\\\\displaystyle\left\left \{ {{b^{2}+10b+25+4b^{2}=85 } \atop {a=b+5}} \right.$

$\displaystyle\left\left \{ {{5b^{2}+10b-60=0 } \atop {a=b+5}} \right.$

$\displaystyle\left\left \{ {{b^{2}+2b-12=0 } \atop {a=b+5}} \right.$

В задании где-то опечатка