Question

5.For an A.P. ,third term is 7, fourth term is 5.Find eighth term. * 2 points -3 3 2 0​

Answer 1

Answer:

a3 = 7

a + (3 - 1) d = 7

a + 2d = 7 -----------------(1)

a4 = 5

a + (4 - 1) d = 5

a +3d = 5 -----------------(2)

subtract eq. (2) from eq. (1), w/g

d = - 2

substitute the value of d in eq. (1), w/g

a + 2( -2) = 7

a - 4 = 7

a = 7 + 4

a = 11

a8 = a + 7d

a8 = 11 + 7 (-2)

a8 = 11 - 14

a8 = -3

Answer 2

Answer:

option a) -3

Step-by-step explanation:

t1, t2, t3= 7, t4=5, t5, t6, t7, t8.

To find: t8

difference between 4th & 3rd term (i.e. 4th - 3rd term)

= 5-7

= -2

thus t5 - t4 = - 2

t5 - 5 = -2

t5 = +5-2 = +3. t5 = 3

similarly

t6-t5 =-2. t6 = 1

t7-t6= -2. t7 = -1

t8-t7= -2

t8 - (-1) = -2

t8 +1 = -2

t8 = -2 -1 = -3. t8 = -3