Simplify the following Expression

`15(20+20i) = `  

Box 1: Enter your answer as a complex number in a+bi form. Example: 2+5i
Enter each value as a number (like 5, -3, 2.2172) or as a calculation (like 5/3, 2^3, 5+4)
Enter DNE for Does Not Exist, oo for Infinity