Find the tenth term and the sum of the first 21 term of the progression _10,_8,_6....
2 answers
I don't know
look at the sequence. Clearly,
a = -10
and d = 2
so that means
a10 = a+9d
S21 = 21/2 (2a+20d)
so plug in your numbers
and BTW, _ is not a minus sign (-)
a = -10
and d = 2
so that means
a10 = a+9d
S21 = 21/2 (2a+20d)
so plug in your numbers
and BTW, _ is not a minus sign (-)
2 answers