The reason fractions need a common denominator before adding or subtracting is so that the numbers of pieces you are adding/subtracting are all the same size. Note that the numerator of a fraction just tells you how many pieces you have of that size.
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Use simultaneous equations:
2x + 7 = x^2 + 8x - 9
7 = x^2 + 6x - 9
16 = x^2 + 6x
+ or - 4 = 7x
answer is
-4/7 or 4/7
Answer:
a.1.90 years
Step-by-step explanation:
We have that to find our 
level, that is the subtraction of 1 by the confidence interval divided by 2. So:
Now, we have to find z in the Ztable as such z has a pvalue of 
.
So it is z with a pvalue of 
, so 
Now, find the margin of error M as such
In which 
is the standard deviation of the population and n is the size of the sample.
In this question:
So
So the correct answer is:
a.1.90 years
Answer:
Susan jogged 1 1/8 miles
Step-by-step explanation:
4 1/2= 18/4. 18/4 ÷ 1/4= 1.125= 1 1/8
