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Which expression is equivalent to (2-5i)(1+3i)-(10-4i)

1 Answer

5 votes

i=√(-1)\to i^2=-1


(2-5i)(1+3i)-(10-4i)\\\\=(2)(1)+(2)(3i)-(5i)(1)-(5i)(3i)-10+4i\\\\=2+6i-5i-15i^2-10+4i\\\\=-8-(15)(-1)+5i\\\\=-8+15+5i\\\\=7+5i
User Corey Coogan
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