<s>[INST] How to i solve this Exponential equation How to solve this exponential equation? 
$$7 \cdot 3^{x+1} - 5^{x+2}= 3^{x+4}- 5^{x+3}$$
 [/INST] $$\\ 7 \cdot 3^{x+1} - 5^{x+2}= 3^{x+4}- 5^{x+3}\\ 125\cdot { 5 }^{ x }-25\cdot { 5 }^{ x }=81\cdot { 3 }^{ x }-21\cdot { 3 }^{ x }\\ 100\cdot { 5 }^{ x }=60\cdot { 3 }^{ x }\\ { \left( \frac { 5 }{ 3 }  \right)  }^{ x }=\frac { 3 }{ 5 } \\ x=-1$$
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