Mathematics Homework Help

Mathematics Homework Help. Find the Intervals on which f(x) is increasing

For the problem f(x)=6x^5/7-x^6/7.

I am getting all the way down to

x^-1/7 = 1/5

They are coming up with the answer 78,125. How are they simplifying to that.

Mathematics Homework Help

 
"Our Prices Start at $11.99. As Our First Client, Use Coupon Code GET15 to claim 15% Discount This Month!!"