Find the sum of the first 40 terms of the arithmetic sequenc

Find the sum of the first 40 terms of the arithmetic sequence: -22, -19, -16,...

a = -22
d = -19 + 22 = -16+19 = 3
S(n) = (n/2)(2a + (n - 1)*d)
S(40) = (40/2)(2*-22 + (40 - 1)*3)
S(40) = 20(-44 + 39*3)
S(40) = 20(-44 + 117)
S(40) = 20 * 73
S(40) = 1460