Question

(5+5i)(5-5i)=what????

Answer 1

Looks like distributive property 5 times 5 is 25, 5 times a -5i is -25i , 5i times 5 is positive 25i , 5i times 5i gives you ,  25 i squared , so now you combine like terms , you have 25 -25i + 25i - 25i squared , cross out -25i and the positive 25i anf your left with 25-25 squared . 

Answer 2

(First,Outer,Inner,Last)
25-25i+25i-25
0