add the real and imaginary parts separately.
2+3i - (3-4i)
2+3i-3+4i
-1+7i
do any others in like wise. note that 6i = 0+6i
1.(2+3i)-(3-4i)
2.6i-(4-i)
2 answers
1. (2+3i)-(3-4i) = 2 + 3i - 3 + 4i = -1 + 7i.
2.
2.