Find the coefficient of x2

Find the coefficient of x² and x in the product of (x – 3) (x + 7) (x – 4).

Answer :

It is given that

(x – 3) (x + 7) (x – 4)

By further calculation

= x³ + (- 3 + 7 – 4) x² + [(-3) (7) + 7 × (-4) + (-4) (-3) + (-3) (7) (-4)]

It can be written as

= x³ + 0x² + (- 21 – 28 + 12) x + 84

So we get

= x³ + 0x² – 37x + 84

Hence, coefficient of x² is zero and coefficient of x is – 3.

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