Write the next term in sequence. Then write a rule for the nth term

2) -5, 10, -15, 20
3) 1/20, 2/30, 3/40, 4/50
5) 2, 6, 12, 20

Plz, only need help on these 3, any explanation or answers is appreciated. Thx!

2)In first sequence, look at the alternate nos. -5 then -15 therefore next is -25
Similarly 10 then20 so next must be 30
So the series..
-5, 10, -15, 20,-25,30
The rule is if the "n" is even,half it and multiply the product by 10
If nis odd the term n would be {-5+(n-1)(-10)}
3)1/20, 2/30, 3/40, 4/50
add one to numerator and ten to denomenator..therefore next nos.are 5/60,6/70 and so on..
The the nth term would be n/10+10n
5) 2, 6, 12, 20
Look carefully...6-2=4
12-6=6
20-12=8
So the series is add 4 then add 6 ..then 8 Therefor you have to add 10 to the next number
20+10=30
then you would add 12
So the next no.is 30+12=42 Therefore the series would be
2, 6, 12, 20,30,42...
HOPE THIS HELPS!!!!

2) -25 [(-1)^n * 5n]
3) 5/60 [n/(10n+10)]
5) 30 [a subscript (n-1) + 2n]

I don't know how to explain it. Either you see it or you don't.