A family is having a pool party built in their backyard. If the Yard is rectangular and measures 10x by 10x in the pool is circular with a radius of 2x how much of the yard will be left over after the pool is built. Write your answer in factored form
1. (100-4pi)x^2
2. 100x^2-4pi(x)^2
3. (100+4pi)x^2
4. 100x^2+4pi(x)^2