Question

if 8th times the 8th term of ap is equal 12 times the 12th term of an ap find the 20th term

Answer 1

this is the answer a=-19,d=1

Answer 2

*:..｡o○☆ HEYA MATE !☆○o｡..:*

GIVEN:

In an AP ,,,

8 t8 = 12 t12

TO FIND :

The 20th term of an AP, t20 = ?

SOLUTION:

The general term,tn

$tn = a + (n - 1)d$

where a is the first term

d is the common difference

n is the nth term of an AP.

8 t8 = 12 t12

8 [ a + ( 8 - 1) d ] = 12 [ a + ( 12 - 1 ) d ]

8 [ a + 7d ] = 12 [ a + 11d]

8a + 56d = 12a + 132 d

8a - 12a = 132d - 56d

-4a = 76 d

a / d = - 76 / 4

a / d = - 19

d = -a /19

SUBSTITUTE THE VALUE OF d ,,

t20 = a + ( 20 -1) d

= a + 19d

= a + 19 ( - a /19)

= a - a

t20 = 0

∝╬══→HOPE U LIKE IT