The nth term of a sequence is given by T= an−b , when a and b are constant If the 5th and 13th term are 10 and 34 respectively . Find the 25th term

Mathematics

ScanSolve AI Answer

Step-by-step solution

4 steps

Let's solve this problem step-by-step.

  1. Set up equations using the given information.

    The nth term of the sequence is given by T = an - b.
    We are given:
    The 5th term (T₅) is 10.
    The 13th term (T₁₃) is 34.

    Substitute these values into the formula:
    For T₅ = 10:
    10 = a(5) - b
    5a - b = 10 (Equation 1)

    For T₁₃ = 34:
    34 = a(13) - b
    13a - b = 34 (Equation 2)

  2. Solve the system of linear equations for 'a' and 'b'.

    Subtract Equation 1 from Equation 2 to eliminate 'b':
    (13a - b) - (5a - b) = 34 - 10
    13a - b - 5a + b = 24
    8a = 24
    a = 24 / 8
    a = 3

    Now substitute the value of 'a' (a=3) into Equation 1:
    5(3) - b = 10
    15 - b = 10
    -b = 10 - 15
    -b = -5
    b = 5

  3. Write the complete formula for the nth term.

    Substitute the values of a=3 and b=5 into the general formula T = an - b:
    T = 3n - 5

  4. Calculate the 25th term (T₂₅).

    Substitute n = 25 into the formula T = 3n - 5:
    T₂₅ = 3(25) - 5
    T₂₅ = 75 - 5
    T₂₅ = 70

    The 25th term is 70.

Was this helpful?

Still stuck on this one?

Ask a follow-up, and the answer starts from this question.

Got a different question?Ask your own question