Question

Check whether 120 is a term of the ap :-3,-1,1....

Answer 1

$\huge\mathfrak\red{Solution}$

• Here a ( First term ) = -3 and d = -1-(-3) = 2 so, d = 2 and an = 120

• We know that,

an = a + (n-1)d

120 = -3 + (n-1) 2

120 = -3 + 2n - 2

120 = 2n - 5

2n = 120+5

2n = 125

n = 125/2 and n is in fraction so it is not the means 120 is not the term for AP

.

Answer 2

Answer:

Step-by-step explanation:

Use an = a + (n-1)d

Substituting

120= -3+ (n-1)2

123= (n-1)2

123/2 + 1 = n

125/2 = n

as n cannot be a fractional value. Thus 120 is not a term of the given AP