PreCal
posted by Kim .
Perform the addition or subtraction and write the result in standard form. (8+sqrt 18)  (4+3sqrt2i) I know that you have to subtract 8 from 4 but I do not know what to do after this.

sqrt (18) = sqrt(1*9*2) = 3 i sqrt2
The two imaginary parts cancel out when you subtract, and you are left with just 8  4 = 4.