How Many Terms Of The Arithmetic Sequence 20,18,16, Must Be Added So That The Sum Will Be -100? With Solution Pls. Thanks<3

how many terms of the arithmetic sequence 20,18,16, must be added so that the sum will be -100? with solution pls. Thanks<3

 

Answer:

n= 71

Step-by-step explanation:

Hello there! Here is the answer for your problem:

Given:

  A₁= 20

  d= -2           18-20

  Sn= -100

  n= ?

Needed Equation:

Sn= 2A₁ + (n- 1) d

-100 = 2 (20) + (n- 1) (-2)    Substitute

-100 = 40- 2n + 2             Simplify

2n = 100+ 40 + 2             Add like terms

2n= 142                           Simplify

n= 71                              Final Answer