Answer:
negative
Step-by-step explanation:
calculating the z score by subtracting the mean and dividing by the standard deviation
(55-70)/10= -1.5
It's negative
Answer: x = -4 or x = 7
Step-by-step explanation:
x^2 - 3x - 28 =/>
(factor)
(x^2 + 4)(x-7) = 0
x + 4 = 0 or x - 7 = 0
(subtract -4 from 0 and 7 from 0)
x = -4 or x =7
Answer:
3
Step-by-step explanation:

And,
$ \sum (2i+1)= \sum (2i)+ \sum_{i=1} ^{4} (1) $
$=\sum_{i=1} ^{4}(2i) + 1+1+1+1 $
$=\boxed{\Big(\sum_{n=1} ^{4}(2n)\Big) +4}.... \text{Variable in Summation doesn't matter}$
Hence the difference is 3.