Hey there :)
To find the slope with <em>two points</em> we will need to use the equation 

( 3 , -20 ) ( 5 , 8 )
Here is what the equation should look like when replaced with the numbers (<em>it will be a fraction</em>) :

We know that <em>two negatives</em> cancel out and make a positive, so the numerator would actually be 8 + 20.
Solve the fraction and we get 
28 <em>divided</em> by 2 is 14. The slope is 14.
We have that
the expression 2f + 4f + 2 – 3-------> we can group it (2f+4f)+(2-3)
(2f+4f)+(2-3)=(6f-1)
therefore
the expression [2f + 4f + 2 – 3] is equivalent to [6f-1]
if the expression [6f-1] for f=3 is 17
then
the expression [2f + 4f + 2 – 3] for f=3 is also 17
<span>let's check it
</span>[2*3 + 4*3 + 2 – 3]--------> [6+12+2-3]=[20-3]=17------> is ok
Answer:
(a) 2%
Step-by-step explanation:
A score of 60 is 2 standard deviations below the mean (80 -2·10 = 60). The empirical rule tells you that 95% of the distribution is within 2 standard deviations of the mean. The remaining 5% is split evenly between those that are more than 2 SD above the mean and those that are more than 2 SD below the mean.
That tells you the percentage who failed is about 2.5%. The best answer choice is 2%.
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<em>Additional comment</em>
The empirical rule is a little bit sloppy, but it gets you in the ballpark. The actual percentage is closer to 2.275%.