((10^x)^3)+4=129 subtract 4 from both sides
((10^x)^3)=125 to cancel out the 3rd power, cube root both sides
∛((10^x)^3)=∛125
10^x=5 use logarithms where 10 is the base (cant figure out how to write it in)
log5 = x plug into calculator log5
x=0.69897