500=0.43*x^1.9 didvide both sides by 0.43
[ 500 / 0.43 ] = x^(1.9) take the log of both sides
log [ 500 / 0.43 ] = logx^1.9 and we can write
[ log 500 / 0.43 ] = 1.9 log x divide both sides by 19
[ log 500 / 0.43] / 1.9 and this says that
10^ ( log ( 500 / 0.43) / 1.9 ) = x = about 41.06
