If the sum of first 9 terms of an A. P is equal to sum of its first 11 terms, then what is the sum of its 20 terms? Pls Anyone help me!!

Put the values into the formula....let me know if you need help....

Step-by-step explanation:

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Step-by-step explanation:

Sum of the first 9 terms = 9/2 (2a + 8d)

Sum of the first 11 terms = 11/2 (2a + 10d)

S9 = S11

9a + 36d = 11a + 55d

2a = -19d

2a + 19d = 0(1)

S20 = 20/2 (2a + 19d)

= 20/2 (0) . .. from (1)

S20 = 0

$655.61 which is option c

step-by-step explanation:

price of house =   $146,000

initial rate = 3.5%

mortgaged paid in this = 3.5 % of $146,000

                                        =

                                        =$5110

the total years would be = 7

total mortgaged paid = 7 * $5110

                                      =$35770

remaining money = $146000-35770

                                =$110230

new mortgaged payment = 5 % of 110230

                                            =  

                                            =$655.61