Question

the product of first 2 tearms of an arithernetic sequence with common difference is 60 is 135 find the first term

Answer 1

your question needs a correction,

6 is written wrong as 60

first term = a

common difference = d = 6

second term = a + d

= a + 6

Product of first and second term = 135

/$\rightarrow a( a + 6 ) = 135 \rightarrow a^2 + 6a - 135 = 0 \rightarrow a^2 + 15a - 9a - 135 = 0 \rightarrow a( a + 15 ) - 9( a + 15 ) = 0 \rightarrow (a + 15 ) (a - 9 ) = 0$

a = - 15 or 9