S = n(a1 + an)/2
2S = n(a1 + an)
2S = na1 + nan
nan = 2S - na1
an = (2S - n a1)/n
it's either a or b, not sure but I think it's b
Answer:
the number is 4
Step-by-step explanation:
we can write this as
x + 15 = 19
now we transpose
x= 19-15
x= 4
Answer:
no
Step-by-step explanation:
6-6=0
1-6=-5