A-level Mathematics/MEI/FP1/Complex Numbers/basic operations solutions

1.

$5j+3j=(5+3)j=8(j)=8j$

2.

$7(3j)=(7)(3)(j)=21(j)=21j$

3.

$(9+2j)(1-j)+3-2j=9-2j^{2}-2j-9j+3-2j=9-11j-(2)(-1)+3-2j=9+2+3-11j-2j=14-13j$

4.

$(21+7j)\div 7=21\div 7+7j\div 7=3+j$

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