Question

5^(2x) - 5^(x+1) + 4 = 0

Answer 1

10Х-5Х+5+4=0
5Х=-1
Х=0,2

Answer 2

5^(2x)-5*5^x+4=0
По теореме Виета:
5^х1=1<=>х1=0
5^х2=4<=>х2=log(5;4)