Answer: C is not correct i just took the test and it was wrong.
Step-by-step explanation:
Similarities: same atomic number
Differences: they have a different number of neutrons
35 50 65 I have to type more because it doesn’t let me answer if I don’t
Answer:

Step-by-step explanation:
simplify
by putting the negative sign on the outside. 
find the LCM of the denominators. It is (x-1)(x-2). Multiply by the LCM:

Simplify:

solve: 
how many times does 5 go into 78
78/5
it goes 15 times with 3 left over (15*5 = 75 75+3 = 78)
15 3/5 ft