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Question

Solve using logarith:
4*72x​ + 7x+1 - 2 = 0

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Solution

4×72x+7x+1-2=0Let 7x=t4t2+7t-2=04t2+8t-t-2=04tt+2-1t+2=04t-1t+2=0t = -2 or 14Now equating the assumed we get, 7x=-2 or 7x= 14But 7x=-2 is not possible because LHS will always be positive. so7x= 14Taking log we get, log7x=log14xlog7 = -log4x = -log4log7=-log74

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