Respuesta :

mhanifa

Answer:

  • 10 and 4

Step-by-step explanation:

The first term is a, common difference is d.

The 6th term:

  • a + 5d = 30

The 12th term:

  • a + 11d = 54

Solve the system by elimination:

  • 11d - 5d = 54 - 30
  • 6d = 24
  • d = 4

Find a:

  • a + 5*4 = 30
  • a + 20 = 30
  • a = 10

jyot010914

Answer:

Given :-

6th term = 30

12th term = 54

To Find :-

First term

Common difference

Solution :-

We know that

[tex] \sf \: a_{n} = a + (n - 1)d[/tex]

For 6th term

[tex] \sf \: 30 = a + (6 - 1)d[/tex]

[tex] \sf \: 30 = a + 5d[/tex]

For 12th term

[tex]\sf \: a_{n} = a + (n - 1)d[/tex]

[tex] \sf \: 54 = a + (12 - 1)d[/tex]

[tex] \sf \: 54 = a + 11d[/tex]

On subtracting both

[tex] \sf \: 54 - 30 = a + 11d - (a + 5d)[/tex]

[tex] \sf \: 54 - 30 = a + 11d - a - 5d[/tex]

[tex] \sf \: 24 = 6d[/tex]

[tex] \sf \: \dfrac{24}{6} = d[/tex]

[tex] \sf \: 4 = d[/tex]

Now

Using 2

[tex] \sf \: 54 = a + 11d[/tex]

[tex] \sf \: 54 = a + 11(4)[/tex]

[tex] \sf \: 54 = a + 44[/tex]

[tex] \sf \: 54 - 44 = a[/tex]

[tex] \sf \: 10 = a[/tex]