Need help with these two problems

Question 18 Suppose we are comparing implementations of insertion sort and merge sort on the same machine. For inputs of size n, insertion sort runs in 8n2 steps, while merge sort runs in 64n Ig, n steps. For which values of n does insertion sort beat merge sort (i.e. takes more steps than merge sort) ? Question 19 What is the smallest value of n such that an algorithm whose running time is 100n2 runs faster than an algorithm whose running time is 2" on the same machine