\(5^x.5^{x+1}.5^{x+2}=3125\)
\(\Rightarrow5^{x+x+1+x+2}=5^5\)
\(\Rightarrow5^{3x+3}=5^5\)
\(\Rightarrow3x+3=5\)
\(\Rightarrow3x=2\)
\(\Rightarrow x=\frac{2}{3}\)
=> 5x.5x+1.5x+2 = 55
<=> 5x+x+1+x+2 = 55
=> x+x+1+x+2 = 5
=> 3x+3=5
3x = 5-3
3x = 2
x = 2:3
x = 2/3
5x . 5x+1.5x+2=3125
5x . 5x .51 + 5x .52=3125
5x . ( 51 + 52 ) = 3125
5x . 30 = 3125
5x = 3125 : 30
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5x .5x+1 .5x+2 = 3125
5x .5x+1 .5x+2 - 3125 = 0
5x+x+1+x+2 - 55 = 0
53x + 3 - 55 = 0
53 ( 53x -52 )=0
53x -52 =0
53x = 52
3x=2
x=2/3