Question

the sum of first q terms of an AP is 63q-3q2.if its pth term is -60 find the value of p.also find the 11th term of this AP

Answer 1

Given Sq = 63q-3q2 
S1 = 63 * 1 - 3* 1*1 
=60 = a1 sum of first 1 term is first term 
S2 = 63 * 2 - 3* 2 *2 
=114 
S2 - S1 = 114 - 60 
=54 = a2 Sum of first two terms - sum of first term is 2 nd term. 
SO , d = 54 - 60 = - 6 
Now, 
ap = - 60 
= a + (p-1) d = - 60 
= 60 + ( p-1) -6= - 60 
= p-1 = -60-60 / -6 
= p = 21 
Now, 
a11 = a+ 10 d 
=60 + 10 *-6 
= 60 + -60 
= 0

Answer 2

your answer is in attach