Find the sum of the first 12 terms of the sequence. if the answer is negative, do not enter any spaces in between the number and the negative sign. 1, -4, -9, -14, . .

Explanation:

The formula to use is

S = (n/2)*(2*a1+d*(n-1))

where

S = sum of the first n terms = unknown

n = number of terms = 12

d = common difference = -5

a1 = first term = 1

So we get the following

S = (n/2)*(2*a1+d(n-1))

S = (12/2)*(2*1 + (-5)*(12-1))

S = 6*(2 - 5(11))

S = 6*(2 - 55)

S = 6*(-53)

S = -318

you can't solve x because it is 2 linear equation and you only have one equation

addition

step-by-step explanation: