Start by subtracting 13 off of both sides so you have the X on one side and the normal on the other side of the equal sign.
so then you have x^(2/3)=4
Then you multiply x by the recipricle so that X is by itself. Whenever you do that, you have to do that to both sides.
so x^(2/3)=4 becomes x^(2/3)(3/2)=4(3/2)
x=8
8 to the 2/3 power = 4, which is from the 17-13 step we did earlier.
x^(2/3)=17-13=4
now take the logarithm of both sides
log(x^(2/3)) = log(4)
and use the logarithm law log(a^b) = b log(a)
=> (2/3) log(x) = log(4)
=> log(x) = (3/2) log(4) = log(4^(3/2))
= log(sqrt(4)³) = log(2³) = log(8)
=> x = 8
Remark : x=-8 is also a solution but normally
we define powers only for positive numbers !