Answer:
7
Step-by-step explanation: (dont trust me)
x^2 + (7)x +18
x(x + 4) + 3(x + 6)
Answer: Tammy's sample may not be vaild because she surveyed the students only from her class and it is likely that other classes might not like the subject maths. She might get the accurate results by surveying a larger number of people in the school instead of just her class.
Answer:
I dont think so I would look at it as how did they get the -2
Given:
Either has a school certificate or diploma or even both = 20 people
Having school certificates = 14
Having diplomas = 11
To find:
The number of people who have a school certificate only.
Solution:
Let A be the set of people who have school certificates and B be the set of people who have diplomas.
According to the given information, we have



We know that,



Subtract both sides by 25.



We need to find the number of people who have a school certificate only, i.e.
.



Therefore, 9 people have a school certificate only.