Help. ​

7^3x  = 400    take the log of both sides

log 7 ^3x  =  log 400      and we can write

3x  *  log 7  =  log 400          divide both sides by 3log 7

x  =  log (400)  / [ 3log (7)]  ≈ 1.026  =  1.03

ln  (4)  + ln (3x)  = 2     we can write

ln  ( 4 * 3x)  = 2

ln (12x )   =  2

This says that

e^2  =  12x            divide both sides by 12

e^2  / 12 =   x   ≈  .615  =  .62