Question

find the nth term

1,7,13,19

find the nth term

15,12,9,6

Answer 1

here,
a=1
b=7
d=7-1=6
now,
n=a+(n-1)d
n =1+nd-d
n=1+nx6-6
n=6n-5
n-6n=5
5n=5
n=5/5=1
hope it's the required answer...
here
a=15
b=12
d=12-15=-3
now
n=a+(n-1)d
n=15+nd-d
n=15+nx(-3)-(-3)
n=15-3n+3
n=18-3n
n+3n=18
4n=18
n=18/4=4.5

Answer 2

Solution....

For First AP-

1, 7, 13, 19.....
a = 1 and d = 6 and n = n.
an = a + (n-1) d
= 1 + (n-1)6
= 1 + 6n -6
= 6n - 5.

For Second AP -
15, 12, 9, 6......
a = 15, d = -3 And n = n
an = a + (n-1)d
= 15 -3n + 3
= 18 - 3n.

⛧⛧⛧⛧For your Extra Question-
12x^3 - 9x^2 = 0
3x^2 [ 4x - 3 ] = 0
so,
3x^2 = 0 and 4x-3 = 0
x^2 = 0 and 4x = 3
x = 0 and x = 3/4.

⛧⛧⛧⛧ For Second Question-
14t^3 + 6t = 0
2t^2 [ 7t + 3 ] = 0
So,
2t^2 = 0 and 7t + 3 = 0
t^2 = 0 and 7t = -3
t = 0 and t = -3/7

⛧⛧⛧⛧⛧⛧ For Third question -
2xy^2 + 8y = 0
2y[ xy + 4 ] = 0
2y = 0 and xy + 4 = 0
y = 0 and y = -4 / x.

Hope this will help you........☺☺☺

☛ ⛧⛧ Mr. Thakur ⛧⛧