Answer : 
Explanation:
Since we have given that
n(U) = 120, where U denotes universal set ,
n(F) = 45, where F denotes who speak French,
n(S) = 42 , where S denotes who speak Spanish,
n(F∪S)' = 50
n(F∪S) = n(U)-n(F∪S) = 120-50 = 70
Now, we know the formula, i.e.
n(F∪s) = n(F)+n(S)-n(F∩S)
⇒ 70 = 45+42-n(F∩S)
⇒ 70 = 87- n(F∩S)
⇒ 70-87 = -n(F∩S)
⇒ -17 = -n( F∩S)
⇒ 17 = n(F∩S)

The answer is -6. because 12,10,8,6,4,2,0,-2,-4,-6.
Answer:
A. A(n) = 150 • (0.74)^n–1 ; 33.29 cm
Step-by-step explanation:
This is a geometric sequence.
a%5B1%5D=1.5m=150cm, r=0.74
The formula is
a%5Bn%5D=a%5B1%5Dr%5E%28n-1%29
Just substitute a1 = 150cm and r = 0.74
a%5Bn%5D=150%280.74%29%5E%28n-1%29
That's the rule.
For the second part, substitute n = 6
cm.