Solve for x

Question

3(5^-x+1 ) = 7^1-x

 

I keep getting an answer of 1 but its wrong. I dont know where Im making a mistake. I multiplied the 3 with the 5 and the exponent.

Answer 1

3(5^1-x) ≠ 15^1-x !!

 

3(5^1-x) = 7^1-x

ln[3(5^1-x) = ln7^1-x

ln3 + ln5^1-x = ln7^1-x

ln3 + (1-x)ln5 = (1-x)ln7

ln3 = (1-x)ln7 - (1-x)ln5

ln3 = (1-x)(ln7 - ln5)

ln3 = (1-x)(ln 1.4)

ln3/ln1.4 = 1-x

-ln3/ln1.4 = x - 1

(-ln3/ln1.4) + 1 = x