Answer:
1.5
Step-by-step explanation:
The mean is the Middle number.
1 standard deviation in both sides of 7.5 makes it between 6 and 9.
<u>What is the </u><u>"common difference"</u><u> in 6 to 7.5 and from 7.5 to 9?</u>

and

So, we would say the standard deviation is 1.5
Answer choice A is right.
Answer:
$25(h) + $130
Step-by-step explanation:
I hope this helps for question a=16
I hope this helps for question b=12
The answer is C and D
First we must make one side of the equation zero, so we subtract 7 on both sides of the equation, making the equation 9x^2 - 6x - 6 = 0
Then we will use the quadratic formula to find the answers.
using the Quadratic Formula where:
a = 9, b = -6, and c = -6
and the formula is 6 +- 