Đáp án:
Giải thích các bước giải:
Đáp án: a.z=3+14i41z=3+14i41
b.z=15i−205169z=15i−205169
Giải thích các bước giải:
a.Ta có:
(4−5i)z=2+i(4−5i)z=2+i
→z=2+i4−5i→z=2+i4−5i
→z=(4+5i)(2+i)(4+5i)(4−5i)→z=(4+5i)(2+i)(4+5i)(4−5i)
→z=8+14i+5i216−25i2→z=8+14i+5i216−25i2
→z=8+14i−516+25→z=8+14i−516+25
→z=3+14i41→z=3+14i41
b.Ta có:
(z+1)(3−2i)2=3i(z+1)(3−2i)2=3i
→(z+1)(9−12i+4i2)=3i→(z+1)(9−12i+4i2)=3i
→(z+1)(9−12i−4)=3i→(z+1)(9−12i−4)=3i
→(z+1)(5−12i)=3i→(z+1)(5−12i)=3i
→(z+1)(5−12i)(5+12i)=3i(5+12i)→(z+1)(5−12i)(5+12i)=3i(5+12i)
→(z+1)(52−122i2)=15i+36i2→(z+1)(52−122i2)=15i+36i2
→(z+1)(52+122)=15i−36→(z+1)(52+122)=15i−36
→(z+1)⋅169=15i−36→(z+1)⋅169=15i−36
→z+1=15i−36169→z+1=15i−36169
→z=15i−36169−1→z=15i−36169−1
→z=15i−36−169169→z=15i−36−169169
→z=15i−205169
