\(\Rightarrow\left(5^2\right)^{4x+2}.\left(5^3\right)^{2x+4}=\left(5^4\right)^4\)
\(\Rightarrow5^{8x+4}.5^{6x+12}=5^{16}\)
\(\Rightarrow5^{8x}.5^4.5^{6x}.5^{12}=5^{16}\)
\(\Rightarrow5^{14x}.5^{16}=5^{16}\)
\(\Rightarrow5^{14x}=1\)
\(\Rightarrow14x=0\)
=> x=0