Answer:
The standard form of a quadratic equation is:
, 
Quadratic Formula Derivation:



Completing the Square:


Square Root property:



To find the mean (average), we first need to add up all the test scores (14 + 19 + 19 + 20 + 16 + 18 + 15 + 17 + 12 = 150). Then, we need to divide that number (150) by the number of numbers in the data set (9 in this case). So the mean of these test scores is about 16.6666666667.
Answer:
Ito
Step-by-step explanation:
Make them to their closest common multiple which is twelve.
Next times 7 by 4 as 3*(4) is 12
Then time 9 by 3 as 3*(4) is 12
7*4=28
9*3=27
Therefore ito washes at a faster rate
0.0000000861 is your answer