3. Find the sum -5.-2,1.431. Solution . Dy lasting all the terms of the sequrner and adding them, we have -5.1-21 - 5+(-2)+1+4+7+ 10 + 11 + 16+19+Z2 + 25 + 30 31 1 22- 169 b. Thus, the sum of the terms of the sequence is 169 ​