Answer:
only the first option is equivalent
Step-by-step explanation:
1) an = a1 + d*(n-1) => a20 = -4 + (-9)*19 = -4 - 171 = - 175
1) ---> C)
2) a81 = 20 + 4*80 = 340;
2) ---> A)
3) a12 = ?
3) ---> B) or D).
Answer:
See below
Step-by-step explanation:

To find the unit rate, divide the numerator and denominator of the given rate by the denominator of the given rate. So in this case, divide the numerator and denominator of 70/5 by 5, to get 14/1, or 14 students per class, which is the unit rate. <— that’s your answer! :)