Question

the 7th term of an ap is -4 and its 13th term is minus 16 find the AP

Answer 1

Hey user here is your answer.......

---> a7=a+(7-1)d
---> a7=a+6d

◆a+6d=-4------(1)

◆a13=-16

◆a+(13-1)d=-16

◆a+12d=-16-------(2)

◆Equation 2-1

◆6d=-12

◆d=-2

◆Put n equation (1)

◆a+6(-2)=-4

◆a=-4+12

◆a=8

◆a1=8

◆a2=a+d
=8-2=6

◆a3=a+2d
◆8+2(-2)

◆=4

Hope it helps you☺️

Regards
#Rohan

Maths aryabhatta

Answer 2

Hii friend,

7th term = -4

a +6D = -4......(1)

and,

13th term = -16

a+12D = -16.....(2)

FROM EQUATION 1 we get,

a +6D = -4

a = -4-6D......(3)

Putting the value of A in equation (2)

a + 12D = -16

-4-6D +12D = -16

6D = -16+6

6D = -12

D = 12/6 = -2

Putting the value of D in equation (3)

a = -4-6D

a = -4 - 6 × -2 = -4+12 = 8

Therefore,

First term = A = 8

Second term = A+D = 8 + -2 = 6

Third term = A+2D = 8 + 2 × -2 = 4.

Fourth term = a+3d = 8 + 3 × -2 = 8-6 = 2

Hence,

AP = 8,6,4,2........

HOPE IT WILL HELP YOU..... :-)