This is the concept of indices. To re-write the question as instructed we proceed as follows: b^-6×b^11 according to the rules of indices, when we multiply the number which have the same base, we add their powers. In our case this will be: b^-6×b^11 adding their powers we get: b^(-6+11) =b^5 the answer will therefore be b^5
11 is one of the factors! The orange divisor(s) above are the prime factors of the number 990. If we put all of it together we have the factors 2 x 3 x 3 x 5 x 11 = 990.
