Question

If the sum of the first 14 terms of an AP is 1050 and its first term is 10 find the 28 term

Answer 1

this would help you
thank you

Answer 2

sum of the 14 terms of an Ap equal to 1050.

first term equal to 10

$sum \: of \: the \: n \: terms \: = s = \frac{n}{2}( {2a + (n - 1)d)$
1050 = 14/2 (2(10)+(14-1)d)
1050 = 7(20+13(d)
1050/7 = 20+13d
150 = 20+13d
150-20= 13d
130 = 13d
130/13= d
10 = d

14 term equal to = a + (n-1) d
= 10+(14-1)10
= 10+13(10)
= 10+130
= 140

therefore 14 term equal to 140.