Answer:

Step-by-step explanation:
Since there are 20 students, this will be the denominator.
Now, to find how many students have a dog and a cat, you need to subtract all the numbers with 20. The leftover number will be the amount of students.
7+8+8=23
23-20=3
So, there are 3 students who have a dog and a cat.
So, the fraction will be 
Y=35 x=110 however im a bit confused on x but im sure on y
Answer:
(7a+y)=(z-4)
Step-by-step explanation:
(7a+y)=z-4
(7a+y)=(z-4)
Answer:
B
Step-by-step explanation:
its not 90 or above because its acute and its not 10 because that would be almost closed so 80 or B is the only answer