Answer:
Kayla sold 90 boxes of cookies.
Step-by-step explanation:
let's have X be the number of boxes Kayla sold.
x⇒100%
18⇒20%
Find x,
x=100/20 × 18
x=90
Given the function f(x)=x^2+5x+5 , to get the zeros we solve using quadratic formula;
x=[-b(+or-) sqrt(b^2-4ac)]/(2a)
from our function;
a=1,b=5, c=5
thus,
x=[-5(+or-)sqrt(5^2-4*1*5)]/(2*1)
x=[-5(+or-)sqrt(25-20)]/2
x=[-5+/-sqrt(5)/2
The answer is option C
So firstly, multiply both sides by 5/7 (reciprocal of 7/5): 
Next, add both sides by 45 and your answer will be: 
Answer:
The last expression 9.
Step-by-step explanation:
hope this helps! let me know if I am wrong
Answer:
Randomized block design
Step-by-step explanation:
In the scenario described above, the subjects which are the different car types are grouped into fixed units of 4 called blocks with each unit then assigned randomly to a particular treatment condition, which are the 4 different types of tire. In the end, the mean mileage for each block is taken and compared to that of the other blocks. This type of research design improves the reliability of the result obtained as it also eliminates the occurrence of systematic error in the course of our experiment.
