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
Answer:
I would say C
Step-by-step explanation:
because I think that 15 is the slope and the 35 is the y intercept. I could be wrong but that would be my guess
Answer:
Step-by-step explanation:
(a). The median number of hours spent on Math was about 2.9 ;
Write an equation based on the problem in the terms of x and solve the equation
first number + second number + third number = 240
x + x + 1 + x + 2 = 240
3x + 3 = 240
3x = 240 - 3
3x = 237
x = 237/3
x = 79
The smallest number, x, is equal to 79
Find the next two numbers
the second number = x + 1
the second number = 79 + 1
the second number = 80
the third number = x + 2
the third number = 79 + 2
the third number = 81
ANSWER: The three numbers are 79, 80, 81
Answer:
v > - 6
Step-by-step explanation:
13 + 2v - 8 + 6 > -7 - v (calculate the sum of difference)
= 11 + 2v>-7-v (move variable to the left-hand side and change its sign and move constant to the right-hand side and change its sign)
= 2v + v > - 7 - 11 (collect like items and calculate the difference)
= 3v>-18 (divide both sides of the inequality by 3)
=v > - 6
*in parentheses is written what to do to get the next number*