Question

find cube of 99 using expansion formula​

Answer 1

ANSWER

We have,

(99)

3

=(100−1)

3

We know that

(a−b)

3

=a

3

−b

3

−3ab(a−b)

Therefore,

=(100)

3

−1

3

−3×100×1×(100−1)

=1000000−1−300(100−1)

=1000000−1−30000+300

=970299

Hence, this is the answer.