5^х + 3*5^х-1 + 2*5^х-2= 42

Question

5^х + 3*5^х-1 + 2*5^х-2= 42

Answer 1

5^x + 3•5^x - 1 + 2•5^x - 2 = 42
5^x • ( 1 + 3•(1/5) + 2•(1/25 )) = 42
5^x • ( 1,6 + 0,08 ) = 42
5^x = 42 : 1,68
5^x = 25
5^x = 5^2
X = 2