[例1] 计算:
(1)(3+5i)+(3-4i);
(2)(-3+2i)-(4-5i);
(3)(5-5i)+(-2-2i)-(3+3i).
[思路点拨] 解答本题可根据复数加减运算的法则进行.
[精解详析] (1)(3+5i)+(3-4i)=(3+3)+(5-4)i=6+i.
(2)(-3+2i)-(4-5i)
=(-3-4)+[2-(-5)]i=-7+7i.
(3)(5-5i)+(-2-2i)-(3+3i)
=(5-2-3)+[-5+(-2)-3]i=-10i.
[一点通] 复数加减运算法则的记忆方法:
(1)复数的实部与实部相加减,虚部与虚部相加减.
(2)把i看作一个字母,类比多项式加减中的合并同类项.
1.(3-5i)+(-4-i)-(3+4i)=________.
解析:(3-5i)+(-4-i)-(3+4i)
=(3-4-3)+(-5-1-4)i
=-4-10i.
答案:-4-10i
2.若(-7i+5)-(9-8i)+(x+yi)=2,则x+y=________.
解析:(-7i+5)-(9-8i)+(x+yi)
=(5-9+x)+(-7+8+y)i
=(x-4)+(y+1)i.
∴(x-4)+(y+1)i=2,