im having problem with this (2+3i) (5-7i) the answer the teacher got is 31+i i got 31-34i what did i do wrong? Thanks, candy
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Originally Posted by Candy101 im having problem with this (2+3i) (5-7i) the answer the teacher got is 31+i i got 31-34i what did i do wrong? Thanks, candy Since you didn't include your working it's impossible to know what you did wrong. However, you would be advised to note that -14i + 15i = i.
oh so sorry first i multiple out (2+3i) (5-7i) and i got 10-14i-20i-21i^2 so i know that i^2 is -1 so ... 21i^2 became 21 giving me 10-14i-20i+21 i then combine -14i with -20i giving me -34i then i added 10 with 21 giving me 31 thanks, candy
Originally Posted by Candy101 oh so sorry first i multiple out (2+3i) (5-7i) and i got 10-14i-20i-21i^2 ... there is your mistake. 3i(5) = 15i ...
omg i see it! gosh thanks!
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