Answer:
The models are different.
Step-by-step explanation:
Yelania and Audrey took two cards which are 4,-6 and 4,6 respectively.
They do not lie on the same points as the sum of Yelania's cards=4-6=-2 and the sum of Audrey's cards=4+6=10.
Both -2 and 10 lie differently on the number line.
Therefore, the models are different from each other.
It looks like you might have intended to say the roots are 7 + i and 5 - i, judging by the extra space between 7 and i.
The simplest polynomial with these characteristics would be

but seeing as each of the options appears to be a quartic polynomial, I suspect f(x) is also supposed to have only real coefficients. In that case, we need to pair up any complex root with its conjugate to "complete" f(x). We end up with

which appears to most closely resemble the third option. Upon expanding, we see f(x) does indeed have real coefficients:

2 and 14/15
Because the first step of subtraction is common denominators
Answer:
1,082
Step-by-step explanation:
The sample size n in Simple Random Sampling is given by

where
z = 1.645 is the critical value for a 90% confidence level (*)
s = 2 is the estimated population standard deviation
e = 0.1 mm points is the margin of error
so

rounded up to the nearest integer.
So the manufacturer should test 1,083 parts.
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(*)This is a point z such that the area under the Normal curve N(0,1) outside the interval [-z, z] equals 10% = 0.1
It can be obtained in Excel with
NORMINV(1-0.05,0,1)
and in OpenOffice Calc with
NORMINV(1-0.05;0;1)