Respuesta :
The answer is that Helene incorrectly used the distributive property by combining the real number and the coefficient of the imaginary part.
Answer:
Step-by-step explanation:
Given that Helene is finding the sum (9 + 10i) + (–8 + 11i).
Also given that She rewrites the sum as (–8 + 11)i + (9 + 10)i.
The mistake she did is in the second term distributing i.
(9+10i) is not equal to (9+10)i
Similarly (-8+11i) is not equal to (-8+11)i
The correct method she should have done is
grouping real terms together and imaginary terms together and finding the sum
[tex](9 + 10i) + (–8 + 11i).\\=9+10i-8+11i\\=(9-8)+i(10+11)\\=1+21i[/tex]
She made a mistake of taking out i from real term without changing the real term appropriately.
Thus she did the mistake of grouping unlike terms and factorising.
