Question

Помогите дам 15 баллов

Answer 1

$\frac{1}{5}=5^{-1};\ 5^{x-1}-5^{-x}=4,96;\ (*5);\ 5^{x}-5*5^{-x}=24,8;\\5^{x}=t;\ t\geq 0;\ t-\frac{5}{t}=24,8;$

t²-24,8t-5=0;

D=615,04+4*5=635,04=25,2²;

t=(24,8+25,2)/2=25;

t=(24,8-25,2)/2=-0,2; ∅;

$5^{x}=25=5^2;\\x=2;$

_____________

0,25=4⁻¹;

$4^x-4^{2-x}=15;\ 4^x-4^24^{-x}=15;\\4^x-\frac{16}{4^x}-15=0;\ 4^x=t;\ t\geq 0;$

t²-15t-16=0;

D=225+4*16=289;

t=(15-17)/2=-1;∅

t=(15-17)/2=16;

$4^x=4^2;\\x=2;$