The 9 term and the 22 term of an A.p are 29 55 respectively,find the sum of it first 60 term and the product of it's 4 and 7 term

Answer 1

a + 8d = 29
a +21d = 55
subtract them
13d = 26
d = 2, then a = 13

sum(60) = (60/2)(26 + 59(2)) = ....
product of 4th and 7th = (a+3d)(a + 6d) = .... plug in your numbers and evaluate

Answer 2

13d = 55-29 = 26, so d=2
a = 29-8d = 13
S60 = 60/2 (2*13 + 59*2) = ____
(13+3*2)(13+6*2) = ____