Answer:
(a) The common difference is 4
(b) The 25th term is 108
Step-by-step explanation:
Given
[tex]T_7 = 36[/tex]
[tex]T_{14} = 64[/tex]
Solving (a): The common difference
The nth term of an AP is:
[tex]T_n = a + (n -1)d[/tex]
For the 7th term, we have:
[tex]36 = a + (7 -1)d[/tex]
[tex]36 = a + 6d[/tex]
For the 14th term, we have:
[tex]64 =a + (14 -1)d[/tex]
[tex]64 =a + 13d[/tex]
Subtract both equations
[tex]64 - 36 = a - a +13d-6d[/tex]
[tex]28 = 7d[/tex]
Divide by 7
[tex]d = 4[/tex]
Solving (b): The 25th term
First, we calculate the first term (a)
The 7th term of the progression is:
[tex]36 = a + 6d[/tex]
Substitute [tex]d = 4[/tex]
[tex]36 = a + 6 * 4[/tex]
[tex]36 = a + 24[/tex]
Subtract 24
[tex]a = 36 -24[/tex]
[tex]a = 12[/tex]
The 25th term is:
[tex]T_{25} = a + (25 - 1)d[/tex]
[tex]T_{25} = 12 + (25 - 1)*4[/tex]
[tex]T_{25} = 12 + 24*4[/tex]
[tex]T_{25} = 108[/tex]
