Binomial Theorem

Question

If the first 3 terms of the expansion of are , find the value of x and n

Solution

Recall the binomial expansion formula



Next we need to simplify



Going back to the question,


We can then form 2 equations involving n and x

Equation 1


Equation 2

Comments

  1. Alternatively, from Eqn (2):

    (nx)^2 - nx * x = 120.

    Also, from Eqn (1),
    nx = -12, (nx)^2 = 144,
    144 - (-12)x = 120
    12x = -24
    x = -2

    This method will avoid denominator..

    ReplyDelete
  2. One just has to be good at the basic mathematical operations, like multiplication, addition and subtraction to understand Vedic maths. Believe us, Vedic maths is this easy.
    supremedissertation

    ReplyDelete

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