Question

15) If the first two terms of an AP are -3 and 4, then what is the 21st term of this AP?



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Answer 1

Step-by-step explanation:

Given in an AP

First term- t1= a = -3

Second term-t2=4

So common difference d =t2-t1

d= 4-(-3)

d=4+3

d=7

So We have to find the 21st term of AP So n= 21

So t21=?

So we have tn= a+(n-1) d

t21= -3+(21-1)7

t21= -3+140

t21= 137

So the 21st term of the given AP will be 137