She made the mistake of grouping unlike terms and factorizing.
Given that
Helene is finding the sum (9 + 10i) + (–8 + 11i).
She rewrites the sum as (–8 + 11)i + (9 + 10)i.
We have to determine
Which statement explains the property of addition that she made an error in using?
According to the question
The mistake she did is in the second term distributing.
(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 given below;
Grouping real terms together and imaginary terms together and finding the sum is,

Hence, she made the mistake of grouping unlike terms and factorizing.
To know more about Complex Number click the link given below.
brainly.com/question/10078818
Hi Brielle the correct answer to your question is 3.12 x 4.0 = 12.48
Option 2:
is the correct answer
Step-by-step explanation:
Given fraction is:

In order to simplify, we can see that the function is already in compact form
So,
We can simplify the given fraction.
We can see that the numerator can be further simplified

Hence,
Option 2:
is the correct answer
Keywords: Polynomials, expressions
Learn more about polynomials at:
#LearnwithBrainly
Ok so we have 7:00 pm and she spends 12 more hours over.
Now lets count up 12 hours
=19
You could also just do 7+12! :)
So therefore, she spend 19 hours had her friends house! :D
Hope this helps!
Given :
A condition :
4 more than one third of a number n is 6.
To Find :
The number n.
Solution :
The given expression in mathematics is given by :

Therefore, the number n is 6.
Hence, this is the required solution.